Not trying to be a jerk or anything, but the "gray/white with a red stripe" in a garage is the equivalent to the "flat black paint with red wheels and whitewall tires" combination you see on a lot of hot rods and motorcycles. There's nothing really wrong with it, its just been done to death.
I think the gray and white would look very nice, just leave out the red. You might even consider doing a multi-shade gray scheme. Pick one or two smaller walls and go with a dark gray, do the rest in a lighter shade, accent/trim with the lightest shade.