Right now, just games/junk browsing, home (personal email, browsing, projects), work (per customer). On Windows I use Sandboxie to further isolate things like browsers.

It's not perfect, but at least when a client wants me to run some damn .exe to join their oh-so-great screen-sharing platform, my home environment isn't messed up. And I can run random games or utilities and quickly revert to a snapshot.

The most sensitive keys stay in the host partition.