The standard cake at our house is a plain-jane Duncan Hines Moist Deluxe Chocolate Swirl cake mix topped with icing and M&Ms in the b-day person's favorite color. The cakes aren't always pretty, but they sure do taste good!
I did go a little off the norm for DHs last bday and used the Duncan Hines pecan something cake mix. (Yes, I love boxed mixes....). I put a nice butter cream icing on top and then topped with finely chopped pecans from Daddy's farm. It was just wonderful!
So, really healthy doesn't enter into the picture much on bdays around here. We just find something that tastes good and go with that.