For the stealth look, the silver can't be beat. Very subtle, very classy look. When you want to look fast even standing still, get a Grand National. When you want to see the jaws drop on Mustang and Camaro owners, paint it silver. Of course, like every other response, I'm a little biased, too. My car is a 1987 WO4 Silver T! I love the look of a freshly waxed black car, but keeping it that way is impossible for a daily driver. The silver looks good from week to week.
I also like the look of the "tuxedo" T: white with black out pkg.