Since it looks like the thread that was in the tech support forum is gone, i thought it would be cool to get a new list going for good free software like AVG or Spybot.
Windows:
Anti-virus
avg free
Office(word, excel, etc)
open office
AntiSpyware
SpyBot Search and Destroy AdAware
Codec
K-Lite
Post anything else you like, i'll move it up here every now and then