My Celestron 10-150x digital microscope. Got it at Fry's Electronics ~$60.00
I epoxied the included plastic clamp to the housing for rigidity, removed the ball swivel from the 1/4"-20 hole, made a bracket & 1/4"-20 thumb screw.
The resolution is phenomenal, focus is a breeze, and the added bonus is that there's a ring of white LEDs built into the housing. Plugs into the USB with some easy-peasy capture software, and voila!