The formatting for my notification email is bad in gmail (it is also wrong in AOL and Yahoo, but not as bad - just missing the baby blue background). I am using the {all_fields} quick code so I am not manually inputting codes.
here is a picture look at the "Birthday Child's Name" field. It is splitting the display in half and inputing '<tr bgcolor="#EAF2FA">' (I covered some of the personal data with a grey box this is not a problem):
http://puzzlesfundome.com/wp-content/uploads/2010/03/form-problem.jpg