San Andreas is a better one than Vice city. There is more of fun,action in SA and a cool gameplay than ViceCity.
I think both are equal but i hate how the car break easily by a little bump unlike the Mafia : The City of Lost Heaven. Dunno with GTA IV. Anyone got reference on other sanbox game?
San Andreas because the gang feature is awesome. U can have like 3 diff gang wars on the same street it gets pretty messy but fun.
I think San Andreas was the best out of all GTA's ever made. So many things you can do in that game. Liberty City just put limitations on the game, they could have made it so much better if they would have stuck with all of the things from San Andreas but just made them better!
I think there still might be a Rockstar sale on Steam where you can pick up the entire GTA collection.