This. Unfortunatey, proof of work concepts for bitcoin are hard to come up with for useful work and we are currently using a modified version of Adam Back's Hashcash to delay people from getting too many bitcoins (his is used to delay people from spamming emails and comments primarily).

Luckily, Bitcoin is not yet a consolidated effort of the brightest minds in the world so there is plenty of room for vital improvements (including removing the proof-of-work requirements of hashing blocks). Unless I'm mistaken, it's also possible to find a solution through Open Transactions.