I work in a department store and asked one of the people who dress the display models and he told me light blue.
Not to sound sexist, but I'm willing to guess these people were either (a.) women, (b.) people with educations in visual arts, or (c.) both. Wearing a pink bottom with a light blue top is common enough for women but not for men in most circles. I used to sell clothing, too, and I could usually spot a man whose wife dressed him: his colors were more like those donned by women, not by men. Probably 90% of the pastel pink-and-green-and-yellow minicheck dress shirts we sold were bought by wives, and a great many of those were returned by husbands. This is not to say that the colors themselves would not look good together; indeed, they would complement each other nicely. However, such a combination on a man who is serious about his wardrobe would probably be just a bit much. I'd go with the suggestions of white or gray, and maybe a dark blue (depending on the exact hue of your pants). EDIT: Okay, okay, I just reread the very passage I quoted and saw that the advisor here was a man. Still, I stand firmly behind what I said.