You can't see fingerprints on the white version.
White iPhone 4 with no fingerprints >>> Black iPhone 4 with fingerprints
In addition to not showing fingerprints the white iPhone 4 also wont get as hot in the car since white reflects light and black absorbs it.
In addition to not showing fingerprints and not getting as hot the white iPhone 4 also is less common than the black version, and will thus have higher resale value on craigslist/ebay
X100. My girlfriend got the white one this morning (and is still freaking out on how awesome it is) and the only thing I like is NO fingerprints appear.