wow thats really strange stuff. I've been using Limewire and OsX for about 6 months now, and haven't seen any of that. It doesn't sound like a memory problem since you have about twice as much memory as me. I have not a clue for you. Osx is very glitchy and Limewire is a glitch - just chalk it up too that.
P.S. - have you ever seen strange black stripes appear across your folders? and what about the Trash? does yours say "cannot empty trash because trash is in use"? try to empty it over and over and all of a sudden it works, for no reason!
without you changing anything? I want to love my mac but its gone insane everysince I installed Osx.