My smartass comment aside, a lot of people say they'll go with white for this very reason.
I just about choked when I read this post here:
Apple - Support - Discussions - Black or white ...
This person obviously is very image conscious and wants everyone to know that he/she has a 16GB model:
"1. It looks more Apple-ish.
2. You can tell by the color it's a 16 GB, and less people will have it.
3. I believe smudges and fingerprints (and possibly scratches) will be much less noticeable."
But if I got white, it would be for the simple fact that it's less common.
My wife thinks she should get white and I should get black so it'll be easy for us to tell them apart. I agree. There were times when almost left the house with each other's Treo 650s.