Bottom line is, PC gaming isn't so different from console gaming as many would believe. Assuming that you like the same games then it comes down to your home setup and the price.
Setup: The only real difference here is screen size (larger TV screen) versus higher resolution. I'm sorry if your desk chair sucks. 5.1 is also available on PCs btw.
Price: If you're serious about gaming (and am I crazy enough to assume that if you're posting in a gaming forum you just might be) then you probably own multiple consoles some of which you bought at launch. Not to mention memory cards, controllers, live accounts. And dont forget to upgrade to the new consoles coming out in a year or two.
The funny thing is people bitch about upgrading their computer for $300-500 every couple of years or so but love talking about their HDTV and 5.1 setup.