I've mentioned Link TV (they recently dropped the "World") here before. Their political coverage is much more important than their music programs. There's an infrequent discussion series hosted by Peter Coyote called "The Active Opposition" that counteracts the talk shows on CNN, Fox etc. beautifully.

The channel also airs lots of foreign documentaries. Previous posts are here and here.

Link TV can be found on DirecTV's channel 375 and Dish Network's channel 9410.

Cheers,
Michael