I recently (about 3 months ago) started using Linux entirely. I had a dual boot machine, but I kept having problems with it, so I reinstalled Linux exclusively. As far as gaming goes, I have steam, onlive and minecraft. I usually play more games on my playstation. My computers are mostly for web browsing and programming. All in all, I am really happy with the decision to switch completely to Linux.
The only problem I am experiencing is that I can't access my iTunes without having a virtual machine. I have an iPhone so that's kind of important, but I've gotten along without it so far.