While the subject of browsers is being floated, does anyone have any good recommendations on how to sensibly achieve two or more concurrent sets of browser data on the same machine?

I have multiple accounts on a few different sites (for generally benign reasons), and I manage this by having one set of logins/cookies/history on Chrome and one set on Firefox. It's a bit of an elaborate assignment problem, especially if I need to maintain three concurrent active accounts in one place.

It would be extraordinarily helpful to have multiple instances of Chrome on one machine (like a Red Chrome, a Blue Chrome and a Green Chrome), which would allow me to keep them separate, but over a consistent environment.