The Parallax BASIC Stamp Activity kit features the very popular BS2 microcontroller, and features a component kit and 350 page manual with 40 projects!
The BASIC Stamp Discovery Kit (USB) is a great way to learn the Basic Stamp.
The Parallax StampWorks Experimenter Kit is a comprehensive collection of everything you will need to learn about efficient embedded design. This is a great package for those who want ALL the accessories!
The Applied Sensors Kit teaches you about interfacing the world to microcontrollers.