I recommend virtualizing Linux. Here's why:
Running WoW and D3 in Wine isn't really that big a deal for most people. You do take a performance hit which will be somewhat noticeable in your framerate, but it's not going to affect you much unless you're running 25-man Dragon Soul or are extremely picky.
From my personal experience running a Core i7 920 and GTX 460 I could do just about everything, but 25 man DS was too much for it. I was getting 6 FPS when lucky on Deathwing and most of the time freezing up for several seconds at a time, usually ending up dead and sometimes wiping the raid. Not good.
With the increased requirements for Mists, I expect no raiding at all, though I had no other real trouble in the beta. (Disclaimer: I help manage the WineHQ page for the MoP beta, which means I get to triage all the bug reports and "it worked for me" posts.)
Also at various points in the last couple of years I've run WoW PTR in VMware (Windows guest, this same Linux host). The performance was similar; 5 mans no problem, but forget raiding.
Diablo 3 wasn't a problem at all; I beta tested it on the very same Linux box and it was smooth and flawless. Ironically I haven't played D3 since release, though I have a copy from Annual Pass...
If I were still an active raider, I would build a separate machine. Linux is my primary OS and I won't dual boot (or give it up) just to game; Windows annoys me too much and just gets in the way of my day-to-day stuff. For anyone whose primary OS is Windows and who's just experimenting with Linux, virtualization is safer and much easier to get started with.
Assuming you already have a valid Win7 product key, virtualize the Linux distribution of your choice. Doing it the other way will probably invalidate your Win7 license, unless it's a full retail Win7. – sawdust – 2012-08-16T05:33:19.317
MS Office should run fine on Wine. Not sure about your games though; check the Wine DB. – Mechanical snail – 2012-08-16T05:49:38.040