I just played Quake 4 for an hour with all settings on high and at 1920 x 1200 resolution. My XFX 7800 GT (which is clocked higher than your GTX) is at 44c. But my ambients inside the case are very low tonight--29.1 by the CPU and 27.5 at the bottom of the MOBO. I have great airflow into my case and the extra 120mm fan on the Scythe Ninja CPU cooler probably pushes some air over the video card as well.
H0witzer, you're obviously watercooling your CPU, what are your ambients in the case?