One quick thought...I usually go to www.digikey.com, whether I end up buying from them or not is another story...
Type 'transistor' in the search box, pick the type of transistor (example Transistor BJT Single under Discrete Semiconductor Products), then narrow it down based on the lists provided. Do it for MOSFETs, chips, resistors, whatever.
I'm sure Digikey isn't the only company that has a 'drill-down' type system for figuring out what a person wants to buy. And I'd be willing to bet that if you know a semi-conductor manufacturer (i.e. Fairchild, Motorola, etc), you'd probably be able to do the same thing at their websites.