STM32F4

RS kindly donated a nice Cortex M4 with FPU development board.

These are really nice to work with. The ARM Eclipse plugin includes a template with everything setup, and I have created a https://zi.is/p/browser/STM32F4_Template with the library for the peripherals and the cross-ARM CMSIS library. This includes semi-hosting and debugging support so is easy to get started with.