Microcontroller suggestion
Aside from Ti's Stellaris family with the Stellaris Launchpad, other Arm/Cortex families will fit the bill. Only other one I know of is STM's STM32 F3 series Cortex-M4, with the Discovery dev kits like the STM32F3DISCOVERY. Basically competing products, but the STM32F303VCT6 is available for individual purchase on Digi-key and such (At 9 bucks in single quantities, sometimes just using the dev board for your project might be a better option). Any of their discovery boards will do what you need for about the same price.

Edit: As an update since the original answer, TI has released a new family based on improvements from the Stellaris line. The Tiva line is in full active production.