Gorman is an excellent, fairly objective play-by-play guy. Both the guys in New Orleans are really balanced and enjoyable to listen to, as well. They're very, very knowledgeable about the league rosters, too.
As for national play-by-play guys, I think my favorite is Mike Breen, which doesn't seem to be a popular opinion on this board. He's always been the neutral one to me, though it may be because he's paired with Jackson and Van Gundy.
As for analyst, it has to be Brent Barry. He's definitely pretty objective and doesn't ride the major stars like other guys. I actually like Webber a lot, too, because he's pretty balanced, as well. Hubie Brown is always great, too.
The worst ones are definitely Mark Jackson and Jon Barry. I find Van Gundy to be amusing, but he's so freaking inconsistent and biased at times it's hard to listen to him. Reggie sucks, too.