Spam me with your political blogs

I’ve got an idea for a new mashup, but I need some help. I usually get my Politik fix on Reddit, so I’m looking for a list of political blogs. General criteria:

1. Should be original content, not aggregators
2. RSS/Atom required, with full posts
3. popular is better
4. opinionated is better
5. Group ‘em by left wing/right wing/centrist (does that exist?) if possible