Voices from the Urban Archipelago - Left of the Dial comprising a short review of Left of the Dial in which the reviewers express surprise that Air America personalities expected there to be money available (based on the NPR model) and whining about the ads on both conservative and liberal talk radio.
My brain has generally learned to tune those pesky things out, although I have to admit that the single background tune used on several ads on my local AM station get somewhat annoying. And XM radio's ads for their other channels are, well, boring. I doubt that many America Left listeners actually are Nascar fans.
But the fact is that the advertising model works to finance talk radio, and the Public Radio model probably won't. Blogs seem to be able to use both models and maybe radio can too. But for right now it's the Advertising model that is being used.