My main OS is Linux (and has been since 2006), but I would have used Win 7 for telescope control if I had got that far. I use Linux for looking things up in Stellarium, Cartes du Ciel, Celestia or in web apps.
INDI is available for Linux - I've never used it and, from what I hear, it's not as feature-rich as ASCOM/EQMOD, but I could be wrong.
If INDI, or similar, were as good as ASCOM/EQMOD, I'd prefer to use Linux for everything.