The folks over at StorageMojo have a battery life comparison of MacBook Airs with hard drives and SSD drives. Also a comparison of MacBook Pros with and without SSD drives.
Anybody with a MacBook Air with SSD care to comment if they’ve got a /.hotfiles.btree file on their machine? This would possibly indicate that Mac OS X is still shuffling around their file system to optimise file access as if it was on a hard drive.