YAY! AVG for your virus protection, Spybot to be run weekly, and bookmark TrendMicro for any other worries. (CCleaner is a good one if you DL and then later delete massive files. It tidies up the joint and makes things more efficient.)

I'm sure someone will have a bunch of great suggestions for you, this is just my method and I'm virus free, have been since the late 90s. :) (But I'm not doing a lot of torrent DL'ding anymore.)