ChuckT: you are wrong about the speed. its got an internal PLL that generates a multiple of the crystal frequency. The Prop is rated at 80MIPS, but faster is possible. There are many firmware blobs you can piece together to do what you want. Already theres Z80 cores implemented in 3 cogs, SID simulations in 1 cog, 3D renderers, you name it. The hardware is quite versatile, and has been used to implement fullspeed (12MHz) usb host mode, emulate the apple II (6502 and RAM were external to the prop) and the list keeps going. I guess I'm a little protective of the prop since I've got a multiboard midi computer in development that uses multiple propellers.
Also, the Cortex M4 Stellaris Launchpad is out for $5 from TI.
