Thank you, I will buy the original first

 To answer napalm's question, I would like to get all the content I can out of the series, and going from an expansion to prophecies may not be as enjoyable.  Besides, from what I hear, the longest game with the most content is prophecies.  I will buy nightfall eventually.

From what I understand, in Guild Wars you have you're main cities where other people are and you can buy/sell items etc., then there are instanced quests that you and your party do.  I am new to Guild Wars and I want to know if I get the original game, are there still people on the original quests and cities?  Or is the original game abandoned and I should just buy nightfall?  If the original is not abandoned, I'd like to get that one first, then Ill buy the expansions as I beat the games. Thanks for your help - Jeremy