iPad speaker... how loud?

I am waiting for my 64GB 3G model to arrive later this month. Can some lucky dog that has one today tell us a little about the built in speaker? How loud is it? Can somebody put their iPhone with a decibel meter and run it by the speaker and give us a reading? Could you hear it on a subway? In a moving car at highway speed? In a noisy restaurant to entertain your kids?

Thanks!