I was going to overclock, as it seems to run faster. I got it pretty close to Ultra speeds, but it's not stable at Ultra speeds. Also, the noise from those teeny fans bothers me. It's the BFG 6800GT OC with the newer, two fan heatsink.
So far, I got a quieter case, quieter HSF(Zalman 7000-Bcu), and slowed down the NB fan using Speedfan(love the K8N-Neo2 with speed controlled NB fan). The one source of noise left is the two fan heatsink on the 6800GT, and I hear the Zalman is quiet and cools well.