What, you're not considering pink?
I have black, and that's the color I'll always recommend to anyone who wants a DS Lite. For the most part, I find that smudge thing to be crap, as it's not as bad as most people make it out to be. Yes, it does get some, but it's not like it's terrible amount of them (unless you really touchy feely with your DS...which is just creepy). And besides, the white one gets them to, you just don't see them as well. What's the big deal in having smudges anyway? Do you really care how the outside of the system looks anyway? If so, you should probably get the black one anyway, because then at least the smudges will be easier to see, and you can clean it easier.
And as for my anti-white argument, sure, it might look nice at first, but over time, which one do you think is gonna look better? Black may get smudges and stuff, but white stains, so in the long run I can guarantee you that a black one will look better than a white one.
So I vote for black, and those are my reasons why. While I want you to pick black, you're gonna win either way, as you're getting one of the best handhelds ever!