I just put the Christmas theme in today; I'll put my normal one back after Christmas. (In Themes, its ExtremeFitness Default). After seeing it in the design area, I decided to get festive!
I just hired a guy to do banners for both my sites - I'll see what he comes up with, but I wouldnt mind seeing what your guy has in mind. Have him drop me a note!
As for the banner, I am using Mozilla and am seeing the snowflake background right through it.