If you follow the Hack-A-Day stream, you’ve probably seen the STM32F0Discovery board come up on occasion. I have two of these boards and I like them — they have what I need for basic stuff, but I wanted some more horse-power (and USB Host.) Quickly, to the STM32F4Discovery!
The target here is people who’ve outgrown the world of AVR and need something running faster; you should be capable and comfortable with diving into your PATH, mucking with environment variables and reading some pretty deep C.
I was given one of these for xmas a little while back (read: 8 months ago) and played with it, getting demo code to run on it. ST did something very painful and/or clever in that they produced this board, for hobbyists, but conveniently forgot to point to a clean, unadulterated compiler.