I prefer utorrent, and have never had any problems. If you want to be paranoid, build a linux box and dl your torrents from there. If you do a lot like I do, you will find its nice to be able to just start a bunch and not have to worry about it since you are free to use your primary computer for whatever else. Also agree with Rage

I use Utorrent. My ISP completerly blocks torrents at certain times of the day. (Limits between 12PM and 5 PM and blocked completerly between 5Pm and midnight) I have had no problems with it. Limewire is a DEFO NO! Stuff from limewire is full of viruses. at least with torrents people put in the comments box's that they contain viruses.

If you are really worried then don't download from torrent websites. Most torrents are illegall anyway. Also don't limit your uploads! It just makes downloads slower for everybody.

i like utorrent better but i think with the right settings its a matter of opinion

Azureus always the best well 2.5.0.4 is... since is uses java client..