which is better?

I was thinking seriously about picking up guild wars, then I saw factions. I don't know anything about either game, except what's on the boxes, and was wondering about the pros and cons of each game. Which offers the most choices character-wise? Which would be a better bet for a new player to pick up? etc, etc... I have the whole diablo series, but that's about all of my experience into the multiplayer world. I'm just looking for some general knowledge about both games, which can help me decide which one to buy.

There are 3 games to get.

Guild Wars:
The biggest campaign of all. Many places to farm, and I find the "presearing" or beginner area to be very enjoyable. Guild Wars will have the most commonly use skills, and you will find that there will be many places to farm. It'll be a while till you get tired. There will be 26 missions

Guild Wars Factions:
The Smallest campaign yet, the leveling goes tons faster then Guild Wars Prophecies (The one above). Many people are disappoint, but this has more grinding areas, missions, and the stuff. Features such as a wide 12v12 battle is in Factions only. Many skills are here, but you will find yourself lacking some skills to farm. Only 13 missions

Guild Wars Nightfall (Coming out in 2 weeks):
Will have the best campaign yet. Not much is known, but it almost rivals Tyria (Guild Wars Prophecie) in size with around 22 missions. Great storyline, imo, GREAT new updates that will be added and the new Hero system which will change guild wars drastically. I can't add much here, but the beginning area for Nightfall was breathtaking.

Its your choice, but I would choose Nightfall, because all the events and updates will mainly affect players in Nightfall. Although I like Tyria the best, go for this.

Get Nightfall! Then Prophesies if you like Nightfall. Buy factions when the price drops to uumm $1.99. Give or take a buck.

Just so you know, all expansions can be combined in one account - they are separate games, but can be linked together, so characters created in one can travel to the other lands.

if you're a completist, I'd suggest getting them in story-order - Guild Wars, then Factions, then Nightfall (released in ~2 weeks, as was said above). Otherwise, you can start with any of them, really.

Yeah, I think factions was a let-down to a lot of people, but prophesies is still an amazing game, and there are lots of high hopes for Nightfall. I'd go with either of the two.

Factions PvE is weaker than Prophenchies PvE

However, if you like PvP, Factions is good. It has some arenas which can be fun. Also you can create assassin or ritualist only in Factions.