Recommended Linux Distros: Mint (for newbies) and Arch (if you know what you're doing and/or want to learn)
I've been using Linux almost exclusively for several months (mostly booting Win7 to update it >_>), even school stuff. Only had a couple small problems w/ LO: the backgrounds in a series of PPTs were screwed up, and a table in a DOC was on top of another one.
Mint is excellent for someone new to Linux; Wubi lets you install in about 4 clicks. I don't use it myself, but my GF loves it. WARNING: the default wallpaper is
very very green. Easy to set-up and tweak, and if you do change your mind, a wubi install's easy to remove.
Arch runs awesome on my kerosene-powered cheese grater! Just don't run out of yogurt

But seriously, it's a great system. A bit like DF actually: rather steep learning curve, but totally worth it. And actually IMO DF's more difficult...
True story: I can't play KotOR on Win7 (crashes every 3-4 minutes), but it runs just fine through Wine, just a couple tweaks. No full-screen though.