Good choice, but don't ever rob yourself with slower memory, especially how cheap Memory is getting. What didn't you go with an Opty though?
I just purchased the 6800GS as well last night. After months of research, lol. 256-256mem bandwith, Intellisample 3.0 Vertex Shaders 3.0 and Pixel Shaders 3.0. My ATI 9700Pro finally seen it's last days. Wow, what a card.