If you find me at a big-money live game, you'll find me in shades. Your eyes are a hard tell to conseal without sunglasses. Sure, I suppose if you practice your poker face enough you could minimize the tell, but for me that would require constant awareness. I want all my mental resources devoted to playing my cards and reading my opponents, not damage control.
One complaint about shades is that they interfer with your vision. I don't think they have to. Your glasses need to be either tinted or mirrored to conceal your eyes, and I agree that tinted glasses used in an already dim room will make gameplay difficult. Mirrored glasses, on the other hand, don't have to be dark barely at all. Even the infamous holographic specs of the "Fossilman" barely darken the view. If you have trouble viewing your cards, you can always try wearing your glasses upside down like TV's Marcel Lewis. He knows the importance of shades is so much that he completely sacrifics style. Nowadays you will find him wearing poker-specific glasses that open at the bottom for easy hole-card access.
Personally, I wear Oakley half-jackets. Nothing about them is specially better for poker then any other good pair, but the ability to easily switch out lenses was a draw for me. I have both a dark tinted lense and the lighter mirrored "fire" lense. If I ever made it to the WSOP main event I'd take the shades off for the camera, but there is no way I would go against the pros without them.