I use Gnutella because it is open source.
I use LimeWire because it is open source.
This means that I trust Gnutella the protocol. But it doesn't mean that I trust LimeWire (recent apparition of Limeshop on osx etc...). Spyware is what pop-up windows were two years ago. Spyware serve to take money from you as popup windows takes time from you to close them. (and if time equals money they are in the same class to me). To fight the popup windows I began using browser killing them (mozilla, safari etc..). To fight the spyware I use spybot on windows and process viewer on os x to indentify malacious add ons and trounce them. I guess the story tells only to be alertl, like everyone should be in every aspect in life. I don't mind the spyware if I can kill it, but some newbies pay for that and thats infortunate.

(I'm still a LW fan, because I admire their hard work and innovation protocol wise but I have to be vigilent and that should be a reflex for everybody.)