I have Livestrong-themed Oakleys and love them. They're super-dark and even though I managed to get a big scratch in them, I don't notice it.

I used to have Rudy Project glasses, I think the "Kerosene" model. Even the slightest scratch on them is visible and annoying. These have been retired from biking. Now I just use them to look cool when I'm off the bike

I don't bother with interchangeable lenses. In low light conditions I wear cheapie yellow safety glasses from the local hardware store. They're light and small enough to carry in a jersey pocket or backpack. These scratch pretty easily, but for $5, I don't really care. I wear them so rarely that it doesn't really matter to me.

In pitch black, I wear clear safety glasses. Same deal, $5 throwaways.

I'm with MartianDestiny on this, no matter the conditions, I wear some form of eye protection. All it takes to give you a bad day is to ride face-first into a spider web or a swarm of bugs!

Max