I loved the Marching Band one last year. I hope someone makes a kickass wallpaper just like that.
I've tried my hand at some personal wallpapers using some of my sideline shots if you don't mind the watermark.
Yeah, I have a basketball one on right now. Need to get me some football on my desktop.
There are some cool old ones at www.theartthearttheart.com, but not sure if he'll be adding new ones this year.