1. Avoid Google and any/all of its products at any cost. If you're not familiar with Eric Schmidt's quote on privacy, look it up on www.startpage.com.
2. This means not using Chrome, Droid OS, Youtube, google.com, and always always using noscript to block any/all google scripts that run on pretty much EVERY webpage in existence. googlesyndication.com and google-analytics.com are huge privacy invaders, as well as everything involved with google. Seriously, avoid them like the plague.
3. If you're not sure how you should be blocking scripts, go to oldapps.com and download firefox 1.5.x (1.5.0.8 and 1.5.0.12 are pretty good stable versions), and then also download NoScript, as an addon to firefox. Set all your stuff to never check for updates because pretty much all the new versions of every browser have all kinds of backdoors and ways for sites to track you much better, especially sites owned by Google.
4. Do not ever use any firewall other than stock windows apps like Defender, Windows Firewall, and please for the love of god install a hardware firewall via a router or another PC running linux, if you care about your privacy and security. I won't go into detail, but if you really dig deep into 3rd party firewall or AV programs, they're basically just backdoors that allow a lot of stuff in, and they frequently phone home to tell other people what you're up to. If you think I'm kidding, then go back to sleep, you're not ready to wake up yet.
TL;DR version: FF 1.5.0.12 + NoScript, no firewall or AV other than Windows Defender, Win Firewall, and Spybot/Teatimer. Hardware Firewall becoming a must have.