This is an absolute nonsense comparison.
The e class is the nicer car, as cars go. They are beautiful things. But this is a stupid comparison, the S5 and the E220d are very different machines with very different performance profiles.
What do you actually want from a car? If you just want a blingcoupe then why would you even consider the S5 over one of the small diesel models?
Also, if you are the type having to look at these on a monthly payment plan, and are budget conscious to be concerned about the price hikes of the premium e class models, then surely you'll not want to put up with the thirst of the S5 anyway.