I know how obnoxious it is when people suggest a brand you're not really interested in, but have you looked at Oakley?
They have some more traditional styles out now, and their sunglasses are basically bomb-proof.
They will send you a new pair of sunglasses for $80.00, no matter what you do to your current pair. I've worn the Spikes for a good three years now, and just swap pairs whenever the lenses get too scratched up.
Plus, after wearing polarized lenses, I'm never going back to plain tinted.
I literally got hit in the face with a refrigerator while helping a friend move a few weeks back, and was surprised not to see any damage to my sunglasses.