iPhone, iPad or Android
..and since Windows phones are more like a bad joke, it would be stupid to support development of games for them.
Sorry for missing a single word... post deleted for lack of relevancy.
On a possible thread derailment side-note:
As for the windows phone, it came too late to the party to have a large part. I would give them a few years (5~7) to become something worthwhile. They are only as much of a joke as most companies first time phone is... then again as I sold my soul to Microsoft I may have a bit of a bias here.
