I wavered between the D and the Ds. Of coarse I wanted the 21.1 megs of the Ds and 5D but I also wanted the 10fps of the D. Most reviews also rated the D superior in the low lighting area. I shoot my boys on dimly lit high school football fields and have had some trouble getting what I wanted out of my Rebel XTi.
I have read nothing but positive comments about your 5D and even spoke to some folks who were selling their Mark III Ds in favor of the 5D.
I'm sorry I forget the ISO on that shot. I was just shooting everything on my first day / evening with the new toy. I think though it was only 800.