I could easily say that I love all the games from the GTAIII era.
1. Vice City (Amazing theme, setting, main character and storyline.)
2. Vice City Stories(Amazing theme, setting, action-packed storyline and Vic's story.)
3. Liberty City Stories (Love the mob vibe in the game. A true mafia storyline.)
4. San Andreas (Although I don't like the "gangsta" theme, I still think this is an awesome game with the variety of missions and settings. Also, the huge map is cool.)
5. GTAIII (Loved it when I first played it, and still do, but after the missions...there's not much else to do)
GTAIV is a great game, but ever since my PS3 blew up, my interest in GTAIV blew up as well...for some reason.