I always wear safety glasses. Fortunately, i have an unlimited supply of them through work.

I did purchase a pair at home depot once (to have a tinted pair), but they did have a high amount of optical distortion. I ended up never using them and always use the clear kind i get at work (they are probably less than $5 each, but i don't really know what brand). I wear a mountain bike style helmet and I've found that the small front visor is typically enough for sunlight.