Firebird, the new, less copy-right-infringing name for Phoenix, which will eventually
replace Mozilla I think, is definitely worth the effort of downloading and configuring it. If I had to use IE again, I would seriously consider just giving up the internet.
Trillian is pretty, but unless you want to try to get the illegal version or pay for it, you might be better off with
GAIM or what I use,
Miranda IM, which is also GPL, but only runs under windows.
I used to use
Winamp quite a bit, but then
Winamp 3 came out, and it sucked bad.
Winamp 2 is still decent, but I've found that
foobar2000 is by far the best audio player I have ever used. It has components galore and only appears to be getting better.