I used to pop on Air America in the car once in a while, before my local affiliate folded altogether...
Nothing against most liberal talkers, but to be honest, I don't WANT to spend too much time listening to them. I don't want to isolate myself in a bubble where I only hear like-minded views until I become detached from reality, like conservatives do with their Fox News/talk radio axis. If I'm forced to listen to radio, I guess I'd have to settle for Lady Gaga or NPR.
As for Pacifica, LOL. Its schedule is totally Balkanized, obscure ethnic music one hour, radical feminists another, crackpot health shows pushing "alternative medicine", underground left-wing hip-hop, then some opera or jazz - you never know what's going to be on, and most of it sucks.
Plus, my local affiliate was involved in some kind of leadership struggle which involved people squabbling on air and locking each other out of the studios at one point, in a desperate battle to dominate their 0.1 Arbitron rating. Radical lefties can be absurd, if you put 5 of them in a room, chances are you'll have four of them dissenting and stomping off to start new factions before they leave.