I haven't played WoW but saw the videos and saw some information.
From what I've seen, WoW is more for the casual players and a tad more social. People claim it to have a better community, I don't know if it is true.
WoW is MMO before RPG: you can craft items yourself, mine, chop wood and sell those items. I'd rather not go on here and instead leave a blank for a WoW player to fill.
Guild Wars, although it claims to be, is not for the casual players. The balance in the game makes almost every skill useful. Menaging your character takes a lot of time and even after you finished the quests and missions, you will still continue to learn about the limits and possibilities of your character. The skill system, like in Diablo, levels with you. Unlike D&D, your most basic healing spells *will* be useful once you reach the level cap (level 20). There is a misconception about GW's drop system: people believe you are unable to get a weapon with good stats. Whereas you can get a good-looking weapon with some rare attributes, you can't find a weapon which would give you an edge in competitive arenas. Frankly, the balance is a little bit annoying sometimes: when you start getting identical attributes for all items you find, it feels wrong. On the other hand, Player-vs-Player would've been impossible without this. Guild Wars is RPG before MMO: you are expected to spend most of your time outside slaying monsters, getting loot and enter towns only to sell everything. The game economy, at the moment, is somehow lacking: unlike WoW, you don't have auction houses so you have to either spam the chat to sell your item or use a website such as
RPG Traders. Finally, since the game isn't easy, you cannot adventure alone (unless you are a Paladin[Warrior/Monk class]). Often you will get clueless players who ignore everyone and blindly charge an enemy group to get the party killed. Nevertheless, there are Leeroys everywhere, as the WoW video proves it <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />.
I hope that helps.
