Qubes OS is excellent for things like that, but not really something most people are willing to use. I love Qubes OS; especially being able to have a disposable

Qubes OS is excellent for things like that, but not really something most people are willing to use. I love Qubes OS; especially being able to have a disposable Windows 7 template VM I can game with that has a PCI passthrough for my spare graphics card. Though, it's a bit heavy for my daily driver laptop. Also, re: your browser idea - checkout the sibling comment to yours on using Chrome with a temporary data directory.