A notice:
DO NOT USE ANY OF THESE WHEN YOU USE TORRENTS. Because you screw up the swarm, and the TOR(my name wooo) network don't have a network capacity to handle torrents

- Tor Inge Røttum (Kj3k53)

Hey, change PeerGuardian to PeerBlock. Same developers, just they discontinued PeerGuardian and started PeerBlock. New name, same thing.

If you want evidence, check this out:
http://www.ghacks.net/2009/08/07/peer-block-con...

tor proxy
http://www.torproject.org/easy-download.html.en
works with Firefox and IE I give it a 9 -10 little leggy when watching streaming videos


to block IP's form coming into your computer i would use p2p guardian :
http://phoenixlabs.org/pg2/
10 -10 stops all incoming and out going connections. A pain to configure but once you do it works really well.

Hotspot Shield: This program secures you from many things.
www.hotspotshield.com