I, of course, agree with both of the above posts.
However, I myself have been torrenting on this computer for three years now, and a while before that too on other computers. Due to memory restrictions (being a gamer, I need all I can get) I have not had a single anti-virus program installed during the entire three year span. I finally got one last night and let it do a full system scan.
The anti-virus was AntiVir, which I decided was the most reliable free anti-virus after much research. It found only one file, which my wife had downloaded of her own volition and I'm pretty sure it's a false positive.
(Just in case, has anyone heard of TR/Small.BQL? It was located in the archive of a well-known non-torrented MMORPG.)
My point is, torrenting can be a terrible thing. If you're pirating software of ANY kind, you are bound to end up with a virus. However, torrenting can also be a very useful tool if used properly. Remember, if you can get something that you should have to pay for for free, odds are you're getting a little more than you bargained for.
I'm honestly surprised that AntiVir didn't find anything after three full years of unprotected surfing and gaming. I mean, I know what I'm doing when it comes to my online safety, but still... I thought being careful would only help to some extent. I think I'm gonna blame all my good fortune on my religious use of Firefox. ^_^