Many guesses as to what she is, any thoughts?

[ToBeEvergreen]

I have what we suspect is a boxer mix, about two years old. Her name is Cassie. She is the goofiest dog we have ever owned.

http://twitpic.com/5skecc
http://twitpic.com/5ussc9

She uses her paws all of the time, especially to play. How she is laying now, she lays down like this a lot, especially when she is tired. She's a great watchdog, and better with people and dogs when we are outside or in another home. She is protective of us and friendly after she has met someone before.

Any guesses? :P