I really like Charlie and Dave but as for national coverage of games, I really like Dan (?) Schulman of ESPN.
I like Gary Thorne for hockey and not so much for baseball.
Locally, I like the Mets radio guys and I really like Gary Cohen of the Mets television crew.
I disagree with Salty: Michael Kay sucks and Jon Sterling could be a great PBP guy if he'd dump the schtick. He calls a great game but it's all the ancillary bullcrap that renders Sterling ineffective.