R3M3 Version I
When I started R3M3, a month ago, I was using a BS2 for the core intelligence. Aside from price, I enjoyed the simplicity of the Basic Stamp. However, I have since been turned onto the cost-effective-tiny-form-factor PICAXE. So I swapped out the BS2 for a 40X and have used a 14M and an old NES Advantage as it's core controller.
Upcoming upgrades include beefier 36mm BaneBot gearmotors, quadrature encoders, and closed loop data logging.