I think I am among the minority of MobileMe customers that takes advantage of the MobileMe gallary integration with iPhoto and Aperture. I find it a very convenient place to share pictures with family and friends, as opposed to my SmugMug gallary for more public photos.
Today Apple released an iPod Touch/iPhone MobileMe gallery app to share your MobileMe photos. It allows you to view your friends' gallaries as well as your own and also gives you the ability to cache photos in your mobile device memory. The App is simple but contains lots of polish. The MobileMe Gallery is free and available in iTunes.