Typical PvE talent setup

After the recent Rupture buffs, combat rogues are presented with two real spec options. The first is for an "Eviscerate only" cycle, which means that besides Slice and Dice, you'll be using Eviscerate as your only damage-dealing finisher. The second choice is a Rupture cycle, which means that you'll be striving for high Rupture uptime first and only using Eviscerate if both Slice and Dice and Rupture have a ton of time remaining. I would typically recommend the first build for any new rogue and for those just learning the combat playstyle. It's far simpler to work with, it is more powerful in heroics and against trash, and it is still pretty competitive with a Rupture build. Unfortunately for the subtlety tree, there's really not anything in there that would attract a combat spec, as poison damage has gotten so powerful that we need the assassination talents to keep pace.

Talent overview

Talents in italics are optional, and you can flex your build to pick up or drop these based on your particular desires. For example, if you choose to not take Weapon Expertise, be sure to pick up a few expertise gems to compensate. If a talent is struck out, avoid it, as it provides little or no benefit to a damage dealer. I'll only be covering the combat and assassination talents that are relevant for a combat rogue to pursue.

• Improved Gouge A PvP-only talent, this has seen its usefulness drop quite drastically, since there aren't many abilities that still require us to be behind our target.
• Improved Sinister Strike A core DPS talent, this improves the efficiency of our main nuke and allows us to maintain a smooth combo-point-to-finisher rotation.
• Dual Wield Specialization A mainstay of every rogue DPS build, our weapon damage has been becoming a larger and larger part of our overall damage package. Since combat rogues focus on white damage as the key factor in their success, DWS is an important part of that equation. It also gives a boost to Killing Spree, one of our most potent cooldowns.
• Improved Slice and Dice By increasing the duration of Slice and Dice, this talent allows us to get more Eviscerates or Ruptures in before having to refresh SnD. It allows our rotations to use fewer points on SnD, which means a solid DPS boost. There's also nowhere else to put these points, and so Imp SnD is really a no-brainer.
• Deflection A PvP or leveling talent, Deflection provides a sizable 6% boost to our parry chance. Its value becomes even more evident when looking at Riposte; however, since we are not struck very often in PvE content, the value of parry is low.
• Precision A free 5% hit and another mainstay of every other DPS spec, as well. The damage benefit per point is insane, and without Precision, every gem on your character would likely be a Rigid King's Amber.
• Endurance Many rogues throw a point in here to move onto the next tree, as the other talents at this tier are pretty weak. By adding a bit of survivability and lowering the timer on some of our cooldowns, it can actually be pretty useful. If this talent lets you get an extra Sprint in on a particular fight, that is actually a true DPS boost.
• Riposte An amazing leveling talent but a terrible PvE talent. We don't parry unless we're being attacked, which would mean we were doing something wrong to start with. Pass this one up; there are plenty of other classes who can slow the target's attack speed.
• Close Quarters Combat Great for the fist/dagger rogue, though swords and axes actually provide top DPS for us at the moment. If you do decide to raid as CQC rogue, be sure that you're not running into the white crit cap in ICC gear. Sword and axe rogues don't run into that issue, as we don't see the 5% crit from CQC.
• Improved Kick PvP only, and not that powerful now that silences share diminishing returns. It can be used to extend your stunlock by an extra two seconds if used properly against a caster.
• Improved Sprint PvP only and really a waste of talent points, with so many good DPS options on this talent tier.
• Lightning Reflexes Formerly a terrible talent that boosted our dodge, Lightning Reflexes is now one of the best DPS talents in the game. By giving us 10% haste for only three talent points, we see a significant boost to our white damage, poison damage and energy generation.
• Aggression While white damage will always be at the top of our damage parses, that doesn't mean we should ignore our special attacks. Aggression boosts the only two specials we'll be using by 15%, so it's really a win-win for us.
• Mace Specialization While the top DPS build in ToC may have been a mace MH build, that was only due to the amazing mace that dropped from heroic Anub'arak. Now, the top-tier weapons are all axes or swords, so mace spec hasn't really seen any love at all.
• Blade Flurry Double damage for 15 seconds? No, even better: It's 20% haste and double damage for 15 seconds. Blade Flurry is a potent CD even on a single target, due to the haste bonus. See if you can coordinate your BF usage with Bloodlust, as haste from different sources stacks multiplicatively, so you want to pop all of your haste boosts all at once. Rogues have no haste cap to speak of, so using Blade Flurry, a Potion of Speed and Bloodlust in unison provides us with the largest benefit. It's also valuable to use any time there are two targets to attack (Twin Val'kyr come to mind) and can also replicate our Fan of Knives attacks. A BF + FoK combo is the most potent AoE attack in the game, and when coupled with Adrenaline Rush to maintain the highest number of FoKs per minute, we are literally gods of AoE damage. Just make sure to give your Tricks of the Trade to a pompous mage or warlock first.
• Hack and Slash Formerly Sword Specialization, the new Hack and Slash also includes axes under its list of approved weapons. This provides us with a significant DPS boost, as off-hand attacks proc an extra main-hand swing, meaning that it actually boosts our white damage by more than 5%.
• Weapon Expertise A great DPS talent, as 10 expertise reduces our chance to be parried or dodged by several percent. If you're finding yourself swimming in expertise on your gear and you can't budge, you can drop a point or two from here and fill out Endurance.
• Blade Twisting A free 10% buff to our main combo point generator and a free chance to snare our target is hard to pass up. This is also pretty useful on an encounter like the Lich King, where snaring a Val'kyr could literally save a life.
• Vitality This bumps our passive energy regeneration rate up from 10 per second to 12.5 per second, allowing us to get more yellow damage done in less time. This doesn't boost the energy gains from anything else like Combat Potency, though it does boost the power of Adrenaline Rush.
• Adrenaline Rush The signature rogue cooldown, Adrenaline Rush provides us with a quick infusion of extra energy. All told, it will yield about 190 extra energy over 15 seconds. This can be very powerful for getting your rotation started quickly when starting a fight or if you are somehow interrupted. Your average five-point Eviscerate (including the Sinister Strikes to get to five points) will cost about 190 energy, meaning that you add a nice boost to your yellow damage while this cooldown is active. It's also particularly effective when coupled with Fan of Knives or Blade Flurry, as this allows you to maximize the effect of both CDs together. Be sure to not use Killing Spree while Adrenaline Rush is active, as you are likely to cap your energy during the Killing Spree duration and lose any energy that you would've been gaining.
• Nerves of Steel A PvP-only talent; no serious rogue will be down the combat tree this deep for PvP, anyway.
• Throwing Specialization Once a powerful addition to our Fan of Knives spam, it's now relegated to being ignored.
• Combat Potency Here's the talent that allows our energy regeneration to scale with our improving gear. This talent alone is the reason that combat is forced to use a quick off-hand weapon, and this talent is what makes haste even more attractive to a combat rogue. Many of the choices a combat rogue makes in terms of gear and weapons will be based on the necessity to maximize the energy gain from Combat Potency.
• Unfair Advantage Possible candidate for coolest attack in the game; unfortunately, it's pretty much a leveling-only talent. Pick this one up for fun on your way to 80!
• Surprise Attacks Originally a DPS loss, Blizzard finally fixed this talent in TBC and it's been great ever since. A nice 10% boost to our only combo point generator is sweet, and the only benefit since having our finishers not be concerned with dodge actually doesn't do anything. Combat rogues have tons of expertise, and so getting dodged doesn't happen to us. It is useful in PvP and against an enemy rogue who has Evasion up (always landing our Kidney Shots rules). At least we get the 10% SS boost!
• Savage Combat Finally, our raid buff! Or, well, our raid debuff! An extra 4% physical damage to any affected target is a pretty big deal, and considering how bad arms warriors are currently, we're really the only raiding spec bringing this to the table. And Blizzard was kind enough to toss in a free 4% boost to our attack power to boot! Savage Combat really saves this tier of talents from being lackluster.
• Prey on the Weak An extra 20% critical strike damage modifier most of the time means that our crits are going to be hitting for huge numbers. Considering we will also have a ton of armor penetration to make us hit even harder, combat rogues can crit for some pretty huge numbers. This talent is active most of the time as our HP is typically topped off (though on certain fights like heroic Anub'arak, that may not be the case).
• Killing Spree Most awesome talent? Definitely. We get to pull off some ninja moves and teleport around, destroying our targets. This can be used to avoid certain boss abilities, like knockbacks or fears. It's affected by Blade Flurry, which means you can completely devastate two targets at once by chaining CDs. If you want to really see the power of Killing Spree, check out this video from my buddy Krytical.

Assassination

• Improved Eviscerate 20% boost to our main finisher? Yes, please!
• Malice A free 5% crit, Malice is one of my favorite talents. Simply and to the point, you'll be critting more often.
• Ruthlessness An unpredictable source of extra combo points; when combined with the Glyph of Sinister Strike, you may be confused when you Sinister Strike once after an Eviscerate yet have three combo points left. It's a DPS boost; just be sure to monitor your CP counter carefully so that you don't waste any procs.
• Blood Spatter Useful if you're going with a Rupture build; otherwise, worthless.
• Lethality Another 30% boost to the critical strike damage bonus of Sinister Strike. When added to Prey on the Weak, Sinister Strike's critical modifier is 50% higher than normal.
• Vile Poisons A simple boost to our poison damage, since the Envenom bonus and dispel protection don't really apply to us.
• Improved Poisons With the newly buffed Deadly Poison mechanic, we really are forced into picking up Improved Poisons to maximize the effect. The particular ratio of talents between Vile and Improved Poisons is very strange, but if you sit down and do the math, 1 to 4 becomes the optimum ratio.

Leveling as combat

Sinister Strike your opponents in the face. Let go of any notion of being an assassin; the leveling combat rogue is a pure brawler. With 11% extra avoidance from Deflection and Lightning Reflexes, you are the tankiest build of rogue around. Don't bother with Stealth. Just run up and attack mobs right in the face. It will be quick and painless (though incredibly dull). Use a CD to wreck a group of mobs, use Blade Flurry to pull two mobs at once, and use Evasion as a DPS cooldown via Unfair Advantage. Find yourself a very slow weapon, and start hitting mobs in the face with it. That's really all there is to it.