And if you are really paranoid....
If you are really paranoid, get a knoppix live cd to do your browsing.
It loads into the ram and doesnt need to even write at all to the HD.
A full fledged linux distro with web browser, email, office suite, etc. It does most of the basic networking for you, given a LAN connection of some sort. IE, with a card, and not a modem.
But you will have to RTFM. I know alot of windows users can't abide that, but that's the way it is.
And of course, you should stop using IE and use Mozilla Firefox on your Windows box, otherwise you most certainly will get that nasty Cool WEb Search and the Porn Dialers.
When Firefox deletes your history, it REALLY deletes it, unlike IE, which as I understand it, has a file somewhere of all hosts visited that it won't erase.
And there's eraser at [url]http://www.heidi.ie/eraser/[/url] to give you a serious clean up that probably will stymie even the FBI from trying to recover your data.
Free. Open Source. Like the Knoppix disk.
Hope this helps!