Check out Sierra Trading Post they got some Serengetis, Oakleys, Smiths, and other stuff on closeout half price... Sierra Trading Post
I got a pair of Smiths "Kenai" w/ amber lens & polarization. They're great for haze reduction and work in well in high and low light conditions and the polarization doesn't pose a problem on any garmin 430/530/1000.

Polarized glasses can be ok you just have to make sure it's ok with the equipment you fly. Because from unit to unit the material that makes up the LCD is polarized at different angles, so are sungglasses. So if you get glasses with one angle that lines up just right with the avionics angle then it may not work...