Gadgetron:
For those that are interested I decided to go with the DFRobotShop Rover V2 - Arduino Compatible Tracked Robot (XBee Kit)
http://www.robotshop.com/dfrobotshop-rover-tracked-robot-xbee-kit-4.htmlThe main reasons I went with this kit: Arduino based, and expandable. Once I get it up and running I am planning on adding a raspberry pi or pandaboard to it and see how far I can push it.
Cool. BTW, I just noticed that you live in Westford, MA. I work in Westford, MA (at IBM) and live in Ayer, MA. I haven't had much time to hack on electronics recently.
o_lampe:
Not sure, what the XBee shields could be used for?
I would imagine you would use the XBee to send commands to the robot wirelessly from another Arduino or from a computer. You obviously would still need appropriate controls for the motors, so I suspect the XBee is in addition to the motor controllers, not replacing them.