so just ordered the game..

but i just bought the 20$ one that said "guild wars" which one is this...
also i have to buy all the other games to be able to play everything?

Guild Wars Prophesies is a fun, stand alone game.
Guild Wars Factions is a fun, stand alone game.
Guild Wars Nightfall is a fun, stand alone game.
Eye of the North is an expansion that can be added to any of these games.
If you buy more than one, & add to the same account, your characters can travel between games.
The benefit of this is the ability to combine skills available only in certain games.
This means your character can do more, that's all.

Actually, to play EVERYTHING, you do need to have all games.

But it's same for all MMOs. Except for City of Heroes/Villains, I think.

GvG? Sorry, only all (maybe except for EotN in some cases) or nothing.
HA the same. TA pretty much the same.

AB - Factions, HvH - Nightfall. RA is the only game you can play with only one campaign, although you will be a lot weaker than people with all campaigns.

Umm... most like, it is the first game, Guild Wars Prophecies, which was never called anything but "Guild Wars" until the other games came out.

Basically, each of the first 3 games provides access to 3 different continents. You can play any one of those games independently. If you own 2 or more of those games, you character from one game can travel to another.

its probaly the first game and you should buy all games

Likely the original, which wasn't called Prophecies until Factions came out, so one could differentiate between the two.

You don't have to, but if you want to play everything, then yes you need to buy everything.

Yeah i only have nightfall and my oppinion it sucks that i cant have all,, so probaly gonna buy some more then

if your serious about playing the game get all,you wont be accepted into any groups for any thing past basic missions if you cant run builds that will require most/all of the games and eye of the north.

I think Wind is talking about pvp, if about pve then they are very much mistaken.

Having all campaigns helps, no question, but I don't think Prophecies was based on skills that would appear in the next campaign