There has been evidence to suggest that there is a seemingly infected copy of limewire about at the moment.
I have personally helped 3 people that installed limewire only to have problems immediately.
After install, it could not be stopped from autostart and it would not uninstall.
There was other malware present, but whether that was already there or not I don't know.
Having said that, it is somewhat irrelevant which P2P client is used.
You have no way of telling if the file you are downloading is infected or not.
Even what looks like an MP3 file could in fact contain a virus.
Unless you are extremely careful, and scan each and every file downloaded at an online scanner such as Jotti or Virus total
then you are at risk of being infected.
Even then you can get caught out, if it is a new variant.
So the basic advice is, unless you are prepared to take the risk, don't use P2P.