More on Chrome's Incognito Mode
As Rick points out, you can use Google Chrome's incognito mode (ctrl-shift-N) to protect yourself from big brother. But there's also another great reason you should use it: multiple gmail accounts at the same time. I'm sick of having to sign out from my main account to check my spam account (that I use when I sign up to try out web services for you guys), my company account, and my adsense account. (Sure, I could forward them to each other, but I barely filter anything as is.)
Of course, the incognito mode--which keeps local cookies--doesn't just work for gmail accounts. I can also now open multiple wordpress accounts, multiple twitter accounts, and more than one Paypal account. Still doesn't offer everything that Firefox does, but it's definitely looking good.