Okay, here's my perspective.
Great build, only a few changes I PERSONALLY would make..
- SLI is such a waste, don't even get into it. Maybe you'll gain 10 or 15 frames per second if you sli a 7800gt or something, but not anything actually worth getting. If you want better performance down the road, I would say stick with the 7800GT which is only like a hundred dollars more than the 6800GS. The GS is a great card, but wont last you as long as the 7800GT performance-wise.
- You're right about not needing to get a psu if you get an Antec Case. Antec makes great psu's and great cases. But don't assume this with all case/psu bundles. Other psu's that come with cases usually suck. Hard ones.
- I'd get this motherboard, great one for overclocking and such for a lot less.
- Why are you buying a TV Tuner? Just curious.