Back when I started messing with electronics as a teenager I started a misc parts bin of resistors, capacitors, LEDs, 555 timers, 7400 logic parts, etc. for my projects. Within a few years that bin grew to a box, to many boxes and now I have a parts closet at home; with each shelf sectioned off for Caps, Inductors, Resistors, Connectors, ICs, etc.
SMT Voltage Regulator Engineering Kit w/ SMT PCBs
Analog IC DIP-Only Design Kit #1 (#1120)
Master Op Amp IC Design Kit #1 with PCB (#1565)
Linear IC DIP-Only Design Kit #2 with PCB (#1310)
There are many more kits at Night Fire's ebay store: http://stores.ebay.com/nightfireelectronickits
Even though I have a closet full of parts at home sometimes getting a small bag of parts stirs my imagination enough to think of my next hack. I just received the Master Op Amp kit and I am ready to build something up!