For sunglasses, I wear Smith Toaster Sliders and Tifosi Quam 1.5s (photochromatic). Both fit small faces very well, although I think the Tifosis are a better value for what you get.
For dark commutes, I wear $5 clear safety glasses from the hardware store. They're a little big, but they wrap around nicely and stay in place. Best of all, I'm not constantly switching between my clear and brown lenses- drives me crazy! I'd rather carry a second pair of glasses for the afternoon ride home.