Meh, I think Wanda Sykes Limbaugh bit was so/so. The treason part was weak, but the "I hope his kidneys fail" was pretty hilarious. Anyway, hand-wringing over Wanda Sykes is pretty useless. She's a comedian. She's not there to respect the line.
Moreover, I think people need to remember the context. Sykes belongs to three groups which Rush has made a career maligning--blacks, gays and women. I don't have time to dig up the Rush-file. But I'm willing to bet that if take together all the abhorrent things Limbaugh has ever said about those three groups and measured them against Sykes few minutes, it wouldn't be a contest.