Well it seems that eventually anything I buy breaks.  I can't really blame this one on bad engineering by Microsoft unlike the 360.  This one was most likely a prolonged exposure to my daughter's mouth.  You see unlike my son, Leah puts everything in her mouth and will chomp or suck on it.  I'm pulled my Zune out of her mouth several times.  Heck I'm on my third pair of headphones this year alone because she puts the ear buds in her mouth.  She went through two sync cables for my iPod as well.  I'm horrible about keeping it out of her reach which doesn't help either. 

In the end the back button is dead as well as the screen.  I was getting sporadic images of the screen and I'd gotten good at navigating the device without looking at the screen.  Now I can't seem to do anything with the device so it's going back home to Microsoft.  I hope I get it back before my trip to the Dells but it's not likely to happen.