I have all those classes 80'd, and at the current patch:
Paladins:
Holy: Good tank healers, not too good group healers, ok in pvp, either as full holy or a prot hybrid.
Protection: A very good tanking tree, while at the same time, blizzard view them as less good than the other classes, so you can pretty much expect buffs, their tanking rotation is more or less static (cooldown limited, not resource limited), best at AoE tanking without sacrificing too much (tanking multiple enemies), in a tanks specc/gear they are pretty bad in pvp as opposed to protection warriors, but pack a punch if you go prot hybrid healer/dps.
Retribution: Easy to play, were overpowered the last few patches, but is now one of the worst to bring in a raid as dps, and exept for "hand of protection" in pvp, they are the worst melee pvper at high ratings.
Rogue:
Asassination: best combo point generation, highest theoretical dps of the rogues talents, mildly OP in arenas atm, especcially in conjunction with a warlock and a healer. Mutilate used to take a minimal amount of "skill" to pull off successfully but now takes around 10 seconds to get into an rotation, and then basically becomes a 2 button class when raiding, envenom is what currently makes some player view them as Overpowered, alot of cooldowns wich can win games, a rogue is nothing without his cooldowns.
Combat: Sustained dps, best energy regeneration without sacrificing too much for it, not the best pvp specc, but killing spree can kill pretty much anything with good enough weapons, this will make arenagame to arenagame vary alot, less theoretical dps then above, but usually pulls it off anyway, as asassination only gets at it peak in certain encounters.
Subletely: A talent tree to put ur leftover talents, used in some pvp builds for extra cooldowns, if you specc this for pve/pvp, people will laugh at you.
Warlock: with the new patch, the typhical melee teams must see themselves beaten by caster combos, decent damage, some utility, all warlock speccs work in raids.
Affliction: You never run out of mana, you rely on ur damage over time spells the most, the typhical pvp build, tho now competes with destruction, ok in raids.
Demonology: Lackluster, brings some buffs to raids, SL+SL aint good anymore.
Destruction: Specialices more similar to a fire mage/ele shaman, you use some dots, but mostly rely on putting up dots wich increases ur charged "bolt" spells, siccritz, very good in pvp atm, aswell as in raids.
I may come back and edit or look at the post, but most likely not.