I'm a huge fan of mafia/crime movies and I quite enjoyed Mafia 2 despite it having a bit of a bad rep. Just go in with lower expectations and think of it as a linear set of missions instead of a real Sandbox game.
Ya, I know, but for only 8 bucks? Damn! And there a few interesting mods for it, like the Freeroam Mod.
I use that mod myself. It's pretty great.
NOTE: I did use the mod on a save that had beaten the game. My memory is a bit fuzzy but I think it messes up some things up if you have it enabled during the campaign itself.