I root for New Jersey.
When I was a little kid the only team called "New Jersey" was the Nets.
My father was a huge sports fan and he followed the Nets, but he was much more concerned with hockey. We watched every single Rangers game - and later the Devils, and if the Nets were on free TV we'd catch an occasional game here and there. I think I was more into it than he was. Some of those Nets teams took a lot of commitment to watch. We actually talked about the NBA more than we watched it. (Maybe that's why I still think hoops is the best sport to read about and talk about.)
I didn't go to too many games, but I did get to see Dr. J's jersey retirement game. (Which was just a happy accident, I'm sure.) I thought it was funny because I was very young and I only knew him as a 76er. They gave out a poster of him standing by a Roman-style pillar that said "All Hail Julius". I hung it in my room. It was the first "enemy" player I ever even considered putting up on my wall. It kind of changed my thinking a bit. I could like players on other teams. Cool! (That thinking led to three things that followed me throughout college - a purple Dan Majerle signature Phoenix Suns cap I ordered off the back of a Tony's Pizza box, A Sacramento Kings cap that most people in South Carolina assumed represented a USFL team or something, and a four foot poster of Patrick Ewing with 3-D sweat so real I always had to resist the urge to towel off the rug underneath it.)
What's strange is that as I got older, I enjoyed watching Nets games more and more while my interest in other sports either stayed the same or declined a bit. I think not being a junkie at seven years old (like with hockey and football and baseball) made it more satisfying somehow. (Believe it or not, I'm starting to feel that way about College Football right now. It's kind of neat how these things evolve.)
When I was a kid, the Nets were mediocre. Buck Williams was the perennial All-Star representative. He was a class act and an easy guy to root for - a great role model. Unfortunately, he wasn't the most exciting player in the world. The Nets' most exciting player was Micheal Ray Richardson (sic), who even then I knew was the opposite of a great role model. They also had the G-Man, Chocolate Thunder, Otis and Albert.
They even drafted my favorite college player of all time - Pearl Washington (!) - who turned out to be a terrible pro. Then things went straight downhill and, IMO, didn't get better until 2001.