I have seen waaaaay too many PC's infected because of Limewire anyway. I have had good results with Morpheus. I like it because it gives you the ability to force all downloaded files to be scanned by your AV software. You have to configure it, but it's there.
Another vote for torrents, but I hated BitLord. Use BitComet.
I have good luck with azureus. Just so you know, torrents take a little more work than just downloading. You have to configure your firewalls and any kind of video is probably compressed.
Just for reference I downloaded a 23.7 gig file in 48 hours. I can't imagine anything that big being offered on any other kind of P2P network and if it were I'd imagine it would take weeks if not months to get. The more popular a file is the faster you can download it. In over 2 years I've never had a virus, the basic concept of torrents pretty much assures you won't get any.
I agree on the torrents being overall better. The main attraction to Morpheus is that it is easier than torrents. You definately have to tell it to go and walk away for a while for a file of any size. It is really only useful for videos/music, but it whoops ass for those.