I'll second the STM32 series of microcontrollers. We're using an STM32F100 chip for instrument control, and it was easy to include it on a custom PCB. It has ma

I'll second the STM32 series of microcontrollers. We're using an STM32F100 chip for instrument control, and it was easy to include it on a custom PCB. It has many timers, and the performance per watt-dollar is amazing (as it is with any ARM chip). The STM32 series can be programmed with the gcc toolchain, or a number of commercial compilers (Keil, etc.). I've taken to using MikroE's compiler: http://www.mikroe.com/mikroc/arm/ http://www.mikroe.com/mikroc/arm/ Another alternative would be TI's Stellaris line. They have an inexpensive "launchpad" dev board: http://www.ti.com/ww/en/launchpad/stellaris_head.html?DCMP=stellaris-launchpad&HQS=stellaris-launchpad-b http://www.ti.com/ww/en/launchpad/stellaris_head.html?DCMP=s... The downside to both of these is that they lack the ecosystem that makes Arduino magical. Before the Due, the Maple board came out to provide an ARM board for the Arduino software: http://leaflabs.com/devices/maple/ http://leaflabs.com/devices/maple/ As a side note, if anyone has experience working with the wireless version of the STM32 (the STM32W), I'd love to hear from you. I'm considering it for another product, but don't want to bother if there are serious problems or if the RF side doesn't work well.