When I glanced at those two posts I got the feeling you were telling him to uninstall it because he was buying the game. I'm glad I read over that a few times and took a moment to notice you were just bashing WoW in general and NOT the fact that he needed help: I'd just ask that you take care to point that out so feelings aren't crossed. I made the mistake easily and other people can aswell.
As for the topic: I'm not familiar with Horde racial abilities, but you can't go so wrong with it you'll want to reroll at endgame just to get the other's, so whatever race you want to be should be free. As for DPS, there's a couple different things you could do suitable to your playstyle:
A warlock has pets (filling various roles, like ranged DPS, tank, heavy melee DPS, caster) that you get as you level up. They primarily throw damage-over-time abilities around in lieu of just hitting something with tons of high-damage attacks.
A hunter also gets pets, but they get to pick theirs from a list of beasts in the game and go tame it. (Pettopia is a great source if you start one, check it out. Google works, should be first hit). They're the rangers of the game and primarily use guns or bows to kill something from range while their pet takes care of it, and they also place traps on the ground to do various things. (Freeze one monster, release a swarm of snakes on another, etc)
Warriors have two damage specs: Arms and Fury. Fury is built more for dual-wielding (at level 60 you can get Titan's Grip, which allows you to dual-wield two 2h weapons) while Arms is built for two-handed combat with huge bursts of damage instead of steady. They also use "rage" instead of mana, which builds as you fight up to 100.
Rogues are actually rather self-explanatory, but they have a "combo" system. As you use an ability, you generally get 1 combo point on the thing you're targeting, up to 5. You have finishing moves which get more powerful depending on how many combo points you have saved up. They also use "energy" instead of mana, which has a cap of 100 as well. Instead of building during the fight, it starts at 100 and abilities drain it by 15-40. It regens constantly at a rather fast rate.
Priests have (arguably) one real damage specialization: Shadow. It's a mixture of damage-over-time abilities and burst damage, but it's real utilization comes at around levels 50 when they can place debuffs on their targets that allow them, based on the damage they do, to regen health and mana of their party memebers.
Paladins(you need Burning Crusade on Horde to play) have the retribution specialization(melee) which focuses around buffing yourself with a certain seal and then whacking things for high burst damage. It's fairly laid-back, at endgame you have three damaging abilities but plenty of ways to customize what type of damage you do depending on what needs done.
Shamans(you need Burning Crusade on Alliance to play) can flip between melee DPS and caster DPS, focusing between dual-wielding and enchanting your weapons with elements (enhancement spec), or throwing thunder bolts (elemental spec).
Mages are primarily based around burst damage, though the Fire specialization has a bit more of a damage-over-time quality, throwing fireballs/frostbolts/arcane blasts depending on which talent specialization you choose.
Druids alternate between one of two things: Shapeshifting into a cat (obtained at level 20, you can use a bear at 10-19, damage spells before that) and dealing rogue-style melee DPS (combo points, energy, and the works) or shapeshifting into a owlkin and throwing nature and arcane bolts.
I know I'm probably forgetting one class, but it'll come back to me. I'm ignoring Death Knights intentionally since it'd require Wrath before you could play one.
EDIT: It's funny how, with a druid as the only character I have at 80 and the only character I play anymore, I left that out.