The Pololu 3pi Robot is a line following and maze solving specialist. The 3pi uses an Atmel AVR ATmega168 processor and is Arduino compatible and has expansion boards available for adding additional features. The most interesting thing about this robot is the speed at which this robot is able to follow lines without any odometery information. The package with everything you need is available for $119.95.
A drone-eye view of the 3D Robotics Tijuana factory team
35 minutes ago