After facing the prospect of giving up my Mac, I have just bought a PC. In the last seven days, I have downloaded:
Ad-aware, SpyBot, Mozilla, Trillian, Winamp, ZipCentral (free .zip utility), Kazaa Lite, Audacity (sound editing), TagScanner (ID3 editing), FreeRIP (ripping), DivX, Roxio DirectCD (packet write), and Folding@home.
I've managed to avoid spending money on software but I do miss iTunes.
I will also be investigating some of the programs listed here and squirreling it all away on a CD-RW for a rainy day.
Thanks for the info everybody.