Vice City Stories if you never played VC/absolutely can't stand top down GTA. Chinatown otherwise.
Objectively Chinatown has the larger amount of content if I remember correctly, but the perspective/artstyle can be off-putting. Being someone whose first game was GTA2(and it's still one of my favorites) I'm completely fine ith the game and would prefer it over the other two. --- "Online gamers are the most ludicrously entitled beings since Caligula made his horse a senator, and at least the horse never said anything stupid."