I had the same first computer. Slapped a 4670 in that sucker. Not a bad machine when it comes down to it.
At some point I'm contemplating getting a 680 or something, but no you're right not a bad machine. Definitely an upgrade from my old compy.
Thanks man! Believe it or not they make some good company to sit on your desk and watch you play video games haha.
Are you trying to suffocate your PSU?
There's more room there then it looks. I'm getting a piece of wood to set my computer on top of so it doesn't come in such close quarters, and I clean the vents daily.