I'm hoping to harness the collective tips of superuser to gather recommended apps/configurations to keep a new desktop clean, virus free, and hopefully lower software rot.
I ask because I've recently come across tools like dropbox, deepfreeze, returnil, etc, and I'm curious what other ones are out there to protect a new box.
I personally am interested in Windows, but feel free to comment on whatever OS you'd like, freeware or otherwise. Ideally specify the price/OS in your answer(s).