I only have one HDD, two optical drives and the graphics card. Oh and a fair amount of USB devices if that counts for anything, though they don't take up much power at all (most have to be plugged into the wall anyways).

My friend also has a nVidia 7800GS, and he said that they require a 450watt PSU. I will read the manual again once I find it though, but yeah, 250watt sounds kind of low.

And I only have to wait at most, 2 minutes before rebooting it.