[Hawkeye]

I used to ride with glasses under goggles (fogging and scratching), then contacts, (dried out all the time) and finally LASIK (in late 1999). I've messed around with a lot of vision combinations, and have a couple of recommendations.
If your glasses will fit under the frames, ProGrip makes a fantastic anti-fog goggle. They are amazing, they simply don't fog. http://www.progrip.com/default.asp?ite=gog
Smith and Wesson made a comfy pair of safety glasses that I picked up at a local contractor store. Their earpeices were more comfortable than the Moose sheilds. This is an option when it isn't dusty, but honestly, with the ProGrip's performance, I wear them all the time. They even worked well trailriding on my birthday when the heat index was 105+ deg. and most sane people stayed inside (love that Iowa humidity).