I have an unhealthy obsession with sunglasses. I wear mine as much as possible. Even at night (kind of lame I know, but I just can't help it). Everyone makes fun of me. But, I just read in some ladies magazine (no, I don't remember which one) that wearing sunglasses protects the skin around your eyes from sun-damage and wrinkles. Plus you don't do that very attractive squinty-eye when it's bright out.
Sooo viva la sunglasses!