I ordered a long and short sleeve T from NBA store for stupid money ($45 I think . . .). Then last Friday (under the influence of whiskey) I made an impulse buy of a red t-shirt with the primary logo at the game for equally silly money. I actually wanted the blue but I had it on order online, and the red looks pretty good and people seem to like it. I was thinking I needed a large, but a medium seems to work for me.
I don't wear "gear".