A great robotics kit for beginners and students is the Vex Robotic kit. That's what I started out with. What's interesting about the Vex robotics kit is that it teaches you some robotics by letting you do it, not just by learning or reading up on it. The starter kit (you can expand on it with other project) gives you everything you need to build your first RC robot. There's also a programming Vex add-on kit for autonomous behaviors. You can buy chain and sprocket kits, tracks kits, sensors like infrared, ultrasound, contact sensors, things like that. You can also incorporate a vision system by using an inexpensive webcam and using a free, very user-friendly robotics vision software called roborealm, which has a module for the Vex microcontroller (I've never used the vision system with the vex design before.) You could probably design and program a robot pretty easily to find its way through a maze with an infrared sensor and some programming.