Open Office isn't exactly compatible with microsoft office I've noticed. Making documents in open office, then opening them in microsoft office, they'll look completely different. Bad scoobies when you're applying online for a job!
I like:
DAMN NFO viewer (for warez)
WinRAR (old school recommended warez app, fuck 7zip, it'll work for ever with no registration)
spybot search and destroy (freeware adware scan)
notepad++ (general note pad shit plus programming shit)
LibreOffice
Microsoft Security Essentials (not good, better than nothing, covers most/all known viruses. But there are ways to detect unknown ones that this doesn't do. You can at least run this side by side with a better AV)
comodo firewall (blah, windows should have a real linux style firewall, fuck the anti virus. Get this, I can make a virus, then make it accepted by the firewall, all through the virus! I've actually done this back in the day)