I get the feeling that if I had an out-and-out favourite camera, I wouldn't have so many cameras...
Based on capability it should easily be my E-M5, but sometimes it seems almost too efficient and is not my favourite camera to look at or hold. Then there is the G1X with its pixel-level perfection, but it isn't the complete package like the E-M5 and is also a bit homely looking from certain angles. My Samsung NX200 has the most wonderful quality materials, controls and display, and finally there is the GH1 which feels more comfortable in the hand than all the others.
They're all my favourites for different reasons.