If you want to level a rogue just for the fun of leveling, go ahead. Rogues are a great class to solo and to level up. I really enjoyed the leveling, although that was 4.5 years ago.

But if you want to level a rogue to have a character to play end-game with, I strongly suggest you should not pick the rogue class. I know, I have played this rogue for 4.5 years.

Pure dps classes are the stepchildren of WoW. The whole game is about hybrids now. As a pure dps class, you will always be considered "just a scrub" who should be happy that he is allowed to come to raids. If you don't believe me, check out the top-10 guilds on your server. I bet that most of those guilds have 1-2, maybe 3 of each pure dps class. But they'll have 4+ druids, shaman, paladins and priests. I bet they even have more warriors and DKs than rogues. Sometimes they run with 6+ paladins and 6+ priests, but only 2 rogues.

Rogues were doing fine dps in Ulduar. Thanks to the buff to our combat talent tree. But in 3.1 something terrible happened. 1) T9.25 gear is hardly an upgrade from T8.25. In fact, getting 3 or less pieces of T8.25 is a downgrade. So any social rogue will let other classes get their T9.25 first. And our dps will fall behind. In Ulduar we had swords, maces, fist and offhand dagger. So after a few weeks, most rogues in a guild would have two new weapons. In ToC there are only 2 axes dropping for us. That means that if you are unlucky, all or most of your rogues will run with Ulduar weapons. Then there is the issue of expertise (too much of it) which makes certain items useless to us.
As a result: rogue dps is not going up as fast as other classes. And when ICC comes, rogues will be doing sub-average dps. And RaidLeaders will not bring more than 1 or 2 rogues to ICC until the whole instance is on farm.

As a rogue, you are a one-trick pony. We can't switch roles when we are bored with dps. And we also can't enjoy the game more by getting offspec sets. Since 3.2 I have gotten 2 upgrades (bracers which are worse than crafted ones) and a BoE cloak. I bought 2 items with BoTriumph. I got all these EoT and EoC in my bag, and nothing I can buy. If I had been a druid, I could have bought healing gear, or boomkin gear. For a rogue, the game is a lot smaller.

Rogues used to be great solo players. Not anymore. In TBC days, I had fun soloing Strat and Scholo in my blue gear (and purple later). I got all T0 sets, just for fun. I soloed recipes. At lvl60 I solo farmed a libram in Dire Maul for an enchant. I soloed GRRP-recipe in LBRS at lvl60. All great fun. But in WLK, there is nothing to solo. The lvl80 instances drop nothing, everything is reputation based. And the lvl70 heroic dungeons are not soloable by a rogue. You will see druids and paladins solo ZG bosses. Warriors were soloing MC bosses at lvl70. DKs can solo well too. But rogues can't solo anything anymore. We can do well for 20-30 seconds, thanks to evasion and maybe stuns. But if a fight lasts longer (and all 70-80 boss fights do), we can't solo anything because we can't heal.

Really, play a hybrid class. The game will be a lot more versatile for you. You can set more goals. You can acquire more loot. You can solo more. You will get a lot more respect.

Rogues might be needed for YS and Anub hardmodes. But how many guilds do that ? 100 in the world maybe ? In a regular guild, rogues are a dime a dozen. And if you don't believe that, you should wonder why so many veteran rogues are leaving this game. More so than any other class.

@gryzemuis - I feel that pain, I think I've had the worse luck of all in Wrath. If it weren't for the expanded badge loot I'd probably still be running in 5man blues/epics & craftables.

I went from my fav fist/sword to having to choose one or the other, and all I've ever won are a couple of OH items. The few times a MH weapon has dropped either our Hunters rolled on it, "Because like, I want the achievement dude", (including all 3 webbed deaths I've seen in 6+ months), or our second rogue won it. I'm down to maces, a BOE drop from Ulduar and that cute mug from Direbrew. The few pieces of leather I've seen drop are usually scooped up by the kitties. Heck, I can't even make use of the spreadsheets anymore, since my level of gear has dropped off the lists.

Despite this horrifying handicap I still manage to be in the top 1-3 dps slots in our 10mans, and in the top 10 in 25mans. It's damn depressing though, to have been raiding for so long, doing Ulduar & ToC with the crap I'm stuck with, and complete lack of rogue-ish drops in these raids. =/