Check out Maglites page they have significantly upgraded the C&D lites. They now have 3 light levels high-medium-Eco. The Eco for D is 58 lumens and C is 20 lumens.
I like the size and form-factor of C sized Maglites, but they always seem to be harder to find and more expensive than their Ds. Perhaps I'll find a nice new C Mag on sale next month for Black Friday...