They're all stand alone. You don't need any other more than the other, but I'd say start with Prophecies as it came out first.

I bought Factions first actually. Then I bought NF and Prophecies at the same time. They are all linked together. I'm sort of addicted :(

Ok, here's a better answer. I'm sure it's too late, but it may help another inquirer: Prophecies, in short, is the hardest of the 3 stand-alone campaigns. It's the first, but most challenging. Big map and nice environments. Factions is the easiest/fastest to level in. You get two additional characters to choose from (Ritualist[pretty versatile] and Assassin[over-powered]). This campaign holds the Alliance Battles (my favorite PvP realm). Nightfall is about as big and as difficult as Prophecies. It has beautiful landscapes and sceneries. There are also cool hidden things like treasures and areas. You get two additional characters to choose from instead of the Rit ans Assassin from Factions. Here you get the Paragon (great melee potential and can support a party) and the Dervish (has the most spells of all melee characters and wields the most powerful weapon [scythe]). Eye of the North is the only expansion and serves as a gateway to Guild Wars two. Beautiful expansion, but as short as one too. To be effective in the game, it would benefit you to get all campaigns so you can unlock all skills (each campaign has a set of skills exclusive to it).

Prophecies, more skills and you can learn how to play better with it :)

By StarFissureThr3e on Jan 14, 2008