I wear KDs ($20) mostly but for a long trip I have a pair of PanOptix that keep the wind and rain out pretty well.
I forgot to mention both pair are polarized.

 

Here's my recommendation. Buy some cheap gas station rack sunglasses and enjoy.

Lose em, crush em, get em stolen, throw them at someone -- doesn't matter. Another gas station around the corner. Buy a new set.

 

ESS Crossbow. Nice wrap around design perfect for motor sports. You can change out the lenses easy and they can be had for about $30 if you shop around on ebay. Issued to active duty in the desert and are ballistic proof:

KEY FEATURES

Tri-Tech™ Fit temples achieve a universal fit with max comfort & zero pressure points
DedBolt™ Lens Lock System keeps lenses secure under impact yet easy to swap
Ballistic 2.4mm high-impact polycarbonate lenses will withstand a shotgun blast from 10 ft.
Advanced ClearZone™ FlowCoat lens treatments eliminate fog inside & prevent scratches outside
ESSOPTICS™ deliver distortion-free optical precision throughout the entire field of view
Quick release lever locks/unlocks lens from frame; lets you replace or exchange lenses in seconds
All lenses provide 100% UVA/UVB protection with precise optical clarity for distortion-free vision
Compatible with ESS Vice™ and P-2B Rx Inserts
Also compatible with APEL-approved U-Rx™ Prescription Inserts
U.S. Patent # D616,485
Compliant with U.S. Federal OSHA, ANSI Z87.1, CE EN 166 and U.S. MIL-PRF-31013.
Black Frame with Smoke Gray or Clear lenses

 

WileyX came out with new lenses that are 80% polarized that allow you to see your digital gauge, cell phone screens, etc. You can only get those lenses through HD. The rest of the WileyX glasses can be had at many retailers.

I just recently picked up three pair of WileyX AirRage glasses for $55.00 each from an online police supplier. They can be had on e-bay from $75 to $100.

 

WOW, I never gave it that much thought.....just grab whatever pair is closest and ride.

 

If you have perfect eyesight, that may work. For the people who need corrected vision glasses or glasses to block wind, dust, etc, there are many choices available but you should try on the frames before buying for proper fit.

 

I recently picked up a pair of Wiley Gravity sunglasses. Today was the first chance I've had to ride with them and I have to say I'm very impressed. These are the most comfortable shades I've ever worn. No wind or dust in my eyes. Yeah, they were pricey, but well worth it.

 

Another one for the Oakley with the interchangeable lenses and wind jacket. If you need RX, there are a couple places that can make them for the Oakley too.

 

mate you need some uglies. great glasses. ugly fish. & good australian product too

 

I'm going to be the buzzkill and say - I don't like the Wiley X's that I bought (from Amazon, btw, not HD).

They look okay and they're fairly comfortable, but they feel cheap to me, the foam gasket adhesive lets go and the foam keeps mushing up into the inside of the glasses, and the lenses (photochromatic) aren't nearly as clear as the lenses on any of my other glasses. Hard to describe, but they're almost like looking through an oil film - not really distorted, but not as clear to me.

I still ride with them on occasion, but I'm looking for another alternative, maybe more of a goggle style...