Rabble.ca is my favourite, but there are only a few good sites out there.
For political news, I like:
http://thetyee.ca/ (BC)
For maps and polling, I like:
http://www.threehundredeight.com/
http://canadianelectionatlas.blogspot.ca/
http://www.electionprediction.org/
Democratic Space was interesting until it shut down.
Issues Pages: