Are You HARDCORE?
Notch recently noted a possible end to the currently-frozen scoring system: experience orbs may begin counting towards a score total in the near future! The recent screenshot also reveals another likely addition, in the form of Hardcore Mode - death means world deletion. At the moment, Minecraft only offers item loss as a potential deterrent from death; the inclusion of an optional Hardcore Mode would certainly provide a new sense of danger and accomplishment to an already excellent game!
(From the Minecraft Forums)