Why spend $300 more for the 2.0GHz unibody MacBook vs the updated 2.0GHz white Macbook? For 200 grams more, with a TFT vs backlit LED screen, you even get a FW port.
Because the build quality on the MacBook (non-Unibody is, and always has been, pretty awful). Those Unibody machines are built to last. Now if they'd just put Firewire 400 back in then I might buy one.