Cap. I don't get sunburn all too often, because I don't spend too much time outside still. When I'm outside I'm moving, and also spend quite some time in the shadow.
I never have too much problems with the light, so I hardly ever wear sunglasses.
A cap, however, I always wear. When outside, that is. Not always in winter of course, but when outside, I think I wear a cap at least 90% of the time. If I don't and there's sun, I feel like my head overheats, and my thinking capabilities lower tremendously. I also tend to get angry much quicker when I don't wear a cap, for some reason.