It's gotta be NBA 2K for me. I remember playing one of the first NBA 2K games back on the PS2. Like NBA 2K4, which I played so much. The controls during the time were unique and interesting. I haven't played many of the recent NBA games, but I've been kind of interested in playing them again.
As for NBA Live. I think I rented one years ago, but it didn't turn out to be so fun. I just never got into the series, and for the most part, it seems people have kind of forgotten about NBA Live.