OK, the ones I've played...
Warhammer Online - It's like World of Warcraft, but PvP and with a far superior community. Although it seems like a tiny thing, the ability to dye your armour is actually massive and almost made me leave Warcraft for good for it. Also, the characters look like they've seen combat, with missing eyes, burn marks and scars all over them, which is awesome. I quit because the developers effectively said that they didn't care about our suggestions because we weren't American, which makes them cunts.
Guild Wars - A cut down version of World of Warcraft you don't have to play for. The game revolves around it's stupidly large number of decently balanced skills rather than the pitifully small number of items, making it far more skill based, relying on combos and strategic skill selection. Sadly, this, combined with the astonishingly awful player base, means that I haven't seen the endgame content for the two that I got. I quit because the players were idiots - I understand you can get custimisable AI teammates in the new games, but I haven't gone back to try them out.
EVE Online - The accountants program of the stars, I played around for a bit, had no idea what I was doing, was shouted down as a noob by anyone I asked, and left after 48 hours, carried on a wave of confusion, boredom and bile. I quit because the players were arseholes and I don't trust anything that levels you while you're offline.
Now, onto ones that aren't on your list...
Age of Conan - It's a bit like World of Warcraft if you like tits and gore. It's been set up so you can play a naked chick all the way through to just before the endgame content. The fighting style is good but takes a lot of getting used to. I quit because, in a game based on Conan the Barbarian, the Barbarian class was the only one that sucked donkey balls, and I wasn't rerolling a pussy-ass Bear Shaman...
City of Heroes/Villains - A faster, more cinematic game than World of Warcraft, City of [X] is also the king of customisation. While it starts slow, by the time you're running around in an eight-man team, combining storms, fireballs and minigun fire while fighting extradimensional aliens, you're loving it. Players are mythical creatures, encountered once in a great while. The story I told about an eight-man team is actually a legend I read once in the forums. I still play this occasionally, but only when I don't want to be bothered by people.
Champions Online - The reason noone plays City of Heroes any more. It currently has less content than some children's books, but it's character creator is amazing and it has a lot of potential. The Nemesis system is a stroke of genius, and there's rumours on the forum of adding "dependant" and "alter ego" systems into the game which might make the entire thing feel like you're playing in your very own superhero comic. The players are a bunch of elitist dickholes, and the addition of a Warcraft-style loot system has resulted in a game that involves grinding and pathetic whingers where heroes should stand.
Anarchy Online - Old and complicated but massive. This is what Warcraft will be like in a decade's time if the old school "hardcore" players have their way. It looks like it was built on the original Unreal engine, so don't go there if you're a graphics whore, but it's pretty cool, and player-owned cities are a nice touch. It's free and, if you really want to try a new MMO, it's worth a shot.
NeoSteam - I... Have no idea what happened while I was playing this. I think there was a plotline, but if nothing else, it's taught me that translations should be done by speakers native to the language. It's pretty much World of Warcraft with flintlock pistols. Unless you like cutesy, anime-style steampunk, avoid.
While I'm rambling about MMORPGs, my "Gamers Don't Know What's Good For Them" award goes to Auto Assault. It's a now-dead game about post-apocalyptic vehicle battles, and it was fucking spectacular - imagine Tabula Rasa in cars with unlimited ammo and no death penalty. And customisable cars. It took me a thousand posts to get this soapbox, and dammit they'll listen to me for a change!
EDIT - Oooh yeah, my opinion! Play Warcraft for a second alt, or pretty much anything on your list, until you get to max level again. When you get to max level, run out the month pissing around and then get Champions Online. The time you gave yourself should get in enough new content to make Champions Worthwhile until The Old Republic comes out - FOR THE LOVE OF GOD, DON'T GET THE OLD REPUBLIC ON RELEASE DAY!
tl;dr? Welcome to a text-based medium of communication.
