Go with the white. The little splash of color brings things together, and the bike doesn't look as 'flat' as the black one (black one is nowhere near as fierce lookin' as the bbq caad9-4). Furthermore, although it'll get dirtier quicker, it'll also be an incentive for you to clean it more often (and provide a better indicator of where you need to clean)

Full disclosure: I just ordered one in black. I checked out the caad10 in white, and before thinking logically about it, I instinctively pulled a batman/bruce wayne/christian bale "does it come in black...". To be fair, black and white does match pretty much everything...