Search filters currently suck
 

The search filter system is WAY too simplistic.
At the very minimum it needs to be changed so you can select multiple filter categories and so you can mark categories as 'negative' ie: marking [Audio] and then the exclude check mark would eliminate the bazillions of mp3 results from a search for an e-book or application.
Making this simple change would make LimeWire jump from good to excellent IMO.