[quote name='javeryh']Vice City is the best GTA to date, IMO.[/quote]
Seconded.
GTA3 was, at the time, amazing to me. I loved the very first GTA (never played the second), but the amount of detail and just fun of the first "3D" GTA world was great. However I do not think it aged very well, and I'm not talking about graphics. There's not a whole to "Fido" and the storyline is pretty straightforward/generic, although some of the supporting characters are interesting.
VC, however, I still think is a great play. The fact that it had a REAL soundtrack and a main character that was entertaining as hell were the sellers. The city was big enough to be interesting, but not so huge that it took forever to get from one area to another. Story isn't great, but it doesn't really take itself seriously (not like GTA3 did anyway) and I definitely felt that at the end of the game I had actually accomplished something - especially that last mission.
SA took a while to grow on me, and although I think it was a step up in terms of the game world itself, it was not as fun to play as VC. Using the word "epic" would be over the top, but the vast space contained in the game world almost reaches that level. What made this game entertaining were the supporting characters (well voiced, as always) and the amount of crap you could do. But the setting, for me at least, just wasn't as attention-grabbing as VC.
Short answer - VC alone is worth it for the variety of missions and sheer joy of playing it. GTA3 is good for historical sake, but there's nothing really earth shattering now about the missions themselves.