I'm going to recommend against getting the strength gear to swap to.

Get healing gear to swap to.

Go as Prot / Holy, and level by staying in LFG, questing anytime there's a curious moment where you don't get in instantly - or need something like say, withirs the mini-pet (alliance) or the sunflower mini-pet (either faction). Or just want to wander around picking flowers (herbalism, cause hey - why not?).

There's no need for DPS gear or a DPS spec unless you want to be a DPS paladin at endgame. And why do that if your goal is tanking.

Going offspec as Holy will teach you a -LOT- about what you can expect out of the healers you get when you tank. Plus Paladin healers heal in melee range, regening by hitting mobs - so it has a similar thrill to melee DPS and tanking. And you can learn a lot about being better at group content from learning how to move around as a mobile healer that relies mostly on non-mobile spells (there's a tricky pickle, but once you learn it - good Paladin healers are the most mobile despite it).

You can grind mobs and level -VERY FAST- in tank spec with tank gear. Especially with LFG going. And you will learn, by level 30, the skills your guild mates tanking for your raid at 85 still can't figure out... (sad, but true).

Arcane Torrent is actually pretty handy to have as an interrupt. It can buy a few seconds against the cultist packs by the golden orbs at the beginning of BoT, for example. In Halls of Reflection where there's more than one shadowlancer in the group, you can stop the AoE shadow damage without switching targets. Incidentally, things get really pissed off at you for silencing them, too. It's a win/win! :D

@Mortenebra: Holy Wrath I think its called, also silences undead - making Arcane Torrent trivial in the Wrath 5-mans. AS has a much shorter cooldown than the 3-mins of Torrent, and often auto-refreshes.

Arcane Torrent is not useless, but its not anywhere near as valuable as it might seem. Since switching from BE to Tauren with the launch of 4.0, I've not missed having it once.

I like arcane torrent for the channeling adds on Alysrazor, during her burnout phase. Between stun, AS, AT, AS, you can keep them totally silenced and unable to even start casting for most of the phase.

However, that's one fight out of.... well, rather a lot :)

@Arcady

I would only say level thru LFG if thats all you want to do at 85 is do dungeons. Otherwise, level how you want. There is no "best way to level" so just break that theory right now. There is a "best way to level for you" but I would say that varies from person to person.

Well if you're leveling a -tank- or a -healer-, then you're making a toon who's only purpose is dungeons. Be they 5, 10, or 25 person.

So the smart money is on LFG.

If you're leveling DPS though, I'd say you've got some leeway to go quest as you might be making a toon for solo use or farming. But if you're making a raid or heroic farming DPSer, its almost more important to LFG PUG - because so many DPS are bad at group teamwork the good ones end up having to do twice the work...

That said, if its your second, third, or in my recent case 6th tank (one of each class horde side, and now a warrior and DK alliance side, all geared up - they've made leveling and gearing too quick and easy since wrath, I can also cart out 4 healers and a DPS) - have fun questing and learning the WoW storyline.