Re: NBA 2K10, NBA 2K11, or NBA 2K13?
2K9 was awesome, really really tough to put down. It was a huge step up from 2K8. 2K7 was awesome too though, I probably spent more time on that game than any of its predecessors.
But yeah, out of the ones you mentioned, definitely get 2K11. The intro of the game the first time you play it gave me chills. Get your hands on 2K12 though if you can.