Head2Head is definitely the best one going right now. Guys are funny, insightful and generally keep things moving even though they can get long, they're rarely boring. Great interviews.
I still listen to K's usually to get my latest news and pinball developments from since I don't have much time anymore to browse Pinside as much as I used to. He often does make good points, although like others said is often hypocritical too.. it's ok though, at least he's not afraid to admit he was wrong on things.. (The Tony Montana bit was one of the most cringe worthy episodes ever though.. couldn't finish that..)
Special When Lit is a nice new one that I've been digging more as well. They came out of nowhere and doing a good job.
I love the short Pinball Profile bite sized episodes / interviews.
Eclectic Gamers is usually pretty good too. I enjoy their perspective on things.
I really miss Pinheadz.. Hope they come back.
The others I used to listen to often I kind of stopped.. they're either way too long, not very concise; too much local tournament talk... some of them just sound horribly bored or tired half the time..