-You can compress the EXE's and Dll's of your program with the free Open Source Program ,,UPX". Many programs uses these compression techniques, to keep their distribution small (e.g. VirtualDub, IrfanView, UltraEdit, HomeSite...).
It protects the user from a overblown program like Windows.
It's free, even for commercial programs !!
Audiograbber uses UPX
You can get UPX here.
http://wildsau.idv.uni-linz.ac.at/mfx/upx.html

-chatting function like in Napster

-ability to ignore Freeloaders

-more better filters (just show servers with available slots e.g.)

more suggestions:

-User option to automatically stop the search after a special amount of time (e.g. 15 minutes)

-Gnotella should remember the statistics from ALL sessions. Not just from the current session