I log into minecraft and the game starts like usual. I can connect to a multiplayer server and start playing fine, but if I click "Single Player" on the main menu, the game instantly freezes and crashes without even displaying the list of saved worlds.

I have tried deleting my bin, resources, etc. folders and redownloading the client, as well as two different JVMs listed above under "Environment." Nothing fixed the problem.

Attached is the crash report from running under OpenJDK 1.6.0_27.