315 Mhash/s with my Sapphire HD 5850, I've also overclocked it to whatever the maximum is in the standard ATI overclocking part of Catalyst Control Center. It's 85 celcius on maximum load at all times.
Download Sapphire Trixx and fix the fan speed higher. You should be able to get it up to 350MH/s easily while keeping a lower temperature.
Definitely, I'm hitting 318 on a 5830. He should be able to pull a whole lot more.