I agree with the original comment about Fox. Can't listen to Joe Buck, though Aikman is solid.
Gus Johnson is decent and excitable, but he's still rough around the edges. He sounds like a really, really good college student announcer, if that makes any sense. Tasker isn't good.
The best play-by-play guy out there, and it's a shame he isn't used more often, is Sean McDonough. He does mainly college football stuff for ESPN, but made his name doing the World Series for CBS in the early '90s. Even then he was in his mid-20s and was one of the best.