There are plenty of fancy smartwatches on the market. Not all of them are designed with makers in mind. The CulBox is an open source watch for Arduino with Bluetooth and sensors for experimentation.
The watch is powered by a 32-bit ARM Cortex processor. It has a 6-axis motion sensor, on-board microphone, 1.5″ OLED display, air pressure sensor, speaker, 3 push buttons, and everything you need to get started. You can build iOS and Android apps for it using RFDuino Simblee Arduino Libraries. CulBox can be yours for $149 if you are an early supporter.