I just managed to corrupt contents of my Eclipse .metadata directory. Starting up with eclipse -clean did not work out. Deleting .metadata and then importing all projects, p
I have some experience at recovering from eclipse when it becomes unstartable for whatever reason, could these blog entries help you?
link (archived)
also search for "cannot start eclipse" (I am a new user, I can only post a single hyperlink, so I have to just ask that you search for the second :( sorry)
perhaps those allow you to recover your workspace as well, I hope it helps.