[setishock]

I use a dark theme as my primary theme. Reason is the darker background makes the images snap off the page. When the same image is viewed on a white or light background it's hard on the eyes. The lighter area around the image makes the pupil in your eye close and you lose the ability to see small details. The darker area around the image allows your pupil to open some and see smaller details.
But like Max I do have a good collection of themes to suit different tastes.
My gallery however is a different story. It's black and gray to make the pics look better.