For my various ECE classes, I've had to buy 2 different kits - one was the development board Kevin posted a link to and the other was one containing resistors all the way from 10 ohms to 10 Mega-Ohms, along with caps from 5 pF to 300uF, various IC's including op amps, 555 timers, simple gates, LED's, pots, various transistors and regulators, a breadboard and a wire kit for it. Its very useful, but I can't say that I would have been tempted to spend $80 on it myself if I wasn't forced to get it for the class. Its made by this company -
http://www.esssales.com/esssales/custom-lab-kits.html but the parts are custom ordered to what WPI wanted for their classes. The FPGA board Kevin posted a link to is extremely useful, because of the nature of FPGA's you are not limited by specific "hardware layers" (not sure if that is the right word really, but you are not limited to an RS-232 serial port or ethernet port), you can implement anything on it until you run out of logic space.