This is great information and advice thanks. I was going to aim for 60Hz refresh, but if that fails, or if 800x600 fails, it will default to windowed mode. It won't affect the gameplay as I'll be using fixed rate logic.
You may want to consider picking a slightly higher refreshrate (75 Hz, or something) if it's listed among the supported resolutions. Most of the time it will look significantly easier on the eyes than the 60Hz does.