My desktop resolution is 1280x960@72Hz. I play most of my games at this resolution and, where possible, at this refresh rate.
When I can't... things go wrong when a game switches resolution (like from the main menu into the game alá AOE2, FEAR etc). The screen goes blank for a few seconds then has multi-coloured (but mostly grey) bands running across it with a big fat warning message in the middle of the screen.
I assume this is happening because my desktop refresh rate doesn't match the game's, but then if I drop my desktop to 1152x864@80Hz, this never happens.
What's going on?! I fear for the life of my crappy monitor!