Its a personal favorite of mine, alongside GTA III and Vice City. GTA IV has the most compelling story of the entire series if you were to ask me (My favorite is still GTA III's story, but IV has the most interesting story.) At the very least, GTA IV's protagonist, Niko Bellic, is by far the most engaging protagonist in the series. Not the most entertaining or intimidating, but Niko is probably the only GTA protagonist who it feels like it'd be good to sit down with and talk to for a while.

For me, it took a long time to get into San Andreas and I still don't like GTA V all that much. San Andreas story never interested me at the start, mainly because I've always hated street gangs and the like, much preferring the organized groups like the Leone Family Mafia and Yakuza of GTA III. And if you could care less about online play like me, since I've always preferred single-player games, GTA V is very forgettable.