I personally feel that there was so much to do in San Andreas that a lot of it felt like a waste. I personally beat all three games 100% and I can just remember being so bored while collecting the oysters and spraying graffiti and doing the endless gang drama. There was no real motivation to do anything.The Rascal King said:San Andreas by a landslide. It was ambitious, engaging, and fun. GTA 3 and Vice city laid an awesome foundation for this game to build on. By the way, do you know how much content they took OUT of the game just so they could finally complete it?
http://gta.wikia.com/Beta_Releases
Sure, San Andreas was a lot of fun to screw around in, but Vice City did such a better job of making you feel tied in with the central plot the whole time... and that's what makes video games so much better than real life.