I will have to second the MBT suggestion. If I am ever in scrubs, MBTs are on my feet. They are perfect for long calls or surgery. I originally thought the curve at the bottom would be hard to stand on for hours straight, but they actually turn out to be a huge advantage when you get used to them. If you're in an all-day surgery, all you have to do is imperceptibly rock back and forth, from the heel to the ball of your foot, and it is completely refreshing.
The only drawback is the price. They are well over $200 new, depending on the model. I wouldn't own a pair if I didn't find a previous year's model at a spa store, of all places, for 70% off. Even then they were pricey, but totally worth it. You really do have to either be extremely rich or find a great deal in order to own them. Mine are some pretty ugly-looking tennis shoes, but they also make professional black leather shoes (for both guys and girls). I've never seen those fancy ones on sale or clearance, though. The entire pediatric neurology division at my hospital wears them as their main clinic dress shoes.