I am very happy with my 1M, but I would be lying if I said the notion of moving on hadn't crossed my mind. I will certainly test the new F30 M3 when it comes out. 4 doors and another 100 hp could be too hard to turn down.
Maybe I will just get a DD and seclude the 1M to track/fun duty. Or maybe I will buy an e36 m3 to build for the track and drive the 1M daily. Really depends on my work and how much I am able to get to the track.