this japanese guy has cranked out a ton of really original, high-quality games in D. They pretty much all have some simple yet engaging and original gameplay design, solid controls, etc. etc. I've browsed through the sourcecode and said "wow, this is really cool/straightforward/neat -- back to work."
I looked at it a little bit; I should take another look. The question would be whether it provides enough benefit over C++ or Objective-C to be worth all the downsides of using a new/oddball language.
(I'm using C++ and ObjC as the litmus because D already has obvious benefits over C in being OOP -- there's no way I'd ever consider using a pure-procedural language -- and over interpreted languages in providing native-code-level efficiency.)
For me it would be compelling if it provided a lot more flexibility and syntactic sugar than ObjC without getting into the mind-bending complexity of C++.