erm help... do you need...

i was wandering if i can just buy nightfall and play or do i need the others?? plz help will be gratefull

Yes, you can buy just Nightfall. Each chapter is "stand alone", which means you can play any one of them all on their own.

Each chapter offers a story to experience, continent to explore, skills, armor and items. Nightfall is a good place to start and if desired you can add other chapter(s) to your account to experience them as well.

This is going to depend on what youre looking for out of the game. If youre looking to just run around with friends and go through the storyline and have fun, then yes you can onyl get Nightfall and accomplish that. If youre looking to explore all the content and maps that Guild Wars has, then no, youll need all 3. If you ever plan to get into PVP, then you MUST have all 3.

NO! You don't need all 3 to play PvP. It definitely helps to have all 3 for being as competitive as possible in PvP, but not necessary. The reason why is that with factions you get 2 additional professions, Assassin and Ritualist (Prophecies has the "core" professions available in each chapter- Mesmer, Monk, Warrior, Necromancer, Elementalist, and Ranger.) There are also many skills available in the other chapters that you can't get in Nightfall -very important for being highly competitvive. BUT, A-Net has made it possible for PvPers to buy skill unlock packs that are substantially less expensive than buying the chapter. They're also a faster way to get the skills needed to run various builds.

ok fine. i should have said this: "You must buy at least a portion of all 3, even still spending 120bux to become competitive."