I'd like to get into robotics using microcontrollers which way to go PIC or AVR or maybe something entirely different. Is there one chip group that is better suited for this type of application... sensors and motor control etc?

I'm no expert, but I believe the major difference is that the AVRs have more internal registers and should be easier to program than PICs. However, there seems to be more pre-made boards and accessories available for the PICs.