Hi:
I'm new to the forum. I've just registered. I work with microcontrollers. I can strongly recommend Atmel AVR microcontrollers as they are real RISC. Atmel has a "motor control oriented" AVR's with lotsa pwm channels and it's Xmega series, 8 bitters also that are IO general control oriented. And are cheaper than PICS. Also the code is portable between micro families (that's why I preferred AVR's over PIC. Pic's change their instruction width between family)
You have C compilers available for free (GNU GCC), and their most useful piece of software is AVR studio, which is used for development and debug and it's free. You have available RTOS firmware for free, for operating system coding, in case you're not going to program the bare metal.
And finally, there are the AVR32 architecture, RISC, well supported (GCC, Linux, FreeRTOS, AVR32 Studio), and ultra high throughput multimedia oriented (AP7 series) or high speed Control /connectivity oriented (UC3X series)
The debug probes are the same for all the AVR microcontrolers (AVR and AVR32) and are cheap. And the microcontrollers indeed are cheap (compared with others with the same capabilities) Even the 32 bitters are head to head in price with the most powerful 8 bitters (to date).
For high precission mixed signal oriented microcontrollers you can check the Silabs microcontrollers. They are 8051 RISC tuned supersets, so most of the existing 8051 code can run on it faster. Their analog performance is very good, as a friend of mine told.
check
www.atmel.com
www.avrfreaks.net
www.silabs.com
winavr.sourceforge.net/index.html
www.freertos.org
Cheers
Nachus