I leveled my first toon to about 30 and that was my Hunter. That was before I even knew the AH existed and Stormwind still had the "gate" closed on Bonechewer, which is an old realm.
I left the Hunter as I was so confused and the core group I played in had only a paladin as a healer, and all melee classes. I did not want to play a mage and so started a Shadow Priest. Since the Pally was a Holy spec it worked perfectly 90% of the time. 70 levels later and TBC ruined PvP for the Shadow Priest as nothing scaled properly.
Then came along my Rogue, who is sitting at 68 right now as being played on and off again. She was rolled to just melee dps, but has been surpassed by my friend who got his rogue to 70 before me, making her semi retired until I feel like getting her to level 70 for Arena fun.
Now I am power leveling a Paladin as we speak. Lots of fun, still can heal, and when it comes to grabbing mobs and having fun, there is not much better. Nothing like soloing melee mobs with Ret Aura, Shield Spike, Consecration, Blessing of Sanctuary, Reckoning, and Redoubt to just make your screen fill up with tons of numbers. I took a screenshot of my lvl 41 paladin taking on 9 mobs at once and what the screen looked like. Many have become Pally Envious due to that pic and to this day some do not realize the strength of a paladin. I will say that they are fairly slow to level at times, but they are damn fun when solo or paired with one other toon. Hoping to get him to level 58 in the next week or two to head over to TBC.