I tend to restart my browser every few sites to keep it clear of cookies and whatnot. Since I use firefox that'll clear my login status as a side effect. Maybe it's total paranoia, but since I only catch 1 or viruses a year, I'll stick with it until it's proven innefective.
Heh, I'll leave my browser open for
hours. Haven't caught a computer virus for, oh, 4 years, I think? And that was only because I hooked up my computer to the Internet while the msblaster virus was going around and before I updated Windows or installed my firewall (because I was logging onto the Internet to do just that!). Before that, I don't think I caught one for over six years. Basically I've never had virus problems since I had my own computer, except that one time while reinstalling Windows on a brand new hard drive (4 years ago).
The real key, it seems, to not catching viruses is:
1. Don't use IE.
2. Don't use MS Outlook/Outlook Express.
3. Have a personal firewall.
4. Keep Windows updated, or don't use Windows.
5. Avoid following links in e-mails unless you know the source (and even then be wary: e-mail viruses send themselves to everybody on your addressbook, so the source still may be somebody you know...fortunately viruses are usually quite easy to pick out).
6. Don't open attachments from people you don't know. Even things like images and documents have been known to include viruses, by exploiting vulnerabilities in various programs.
7. Virus-check things you download unless you know the source.
8. Be especially careful when downloading anything dodgy.
9. Oh, yeah, and have a virus scanner active.
I think that about covers it.