When I was looking for a plug to fit into a Yaesu charger that I inherited, I was referred to Part Express. The not only had the part, but a lot of other interesting stuff as well.
They mostly specialize in consumer electronics, but they carry a bunch of stuff that will be useful to ham radio operators. Their holiday flyer, for example, offers a variable temperature soldering iron for $12.00 and a 12V, 2A power supply for $12.00. Prices are good until January 4, 2010.
The second catalog I actually got a couple of months ago. It’s the catalog for Small Parts: The Hardware Store for Researchers and Developers. They claim to have over 100,000 products.
For example, they carry all different kinds of wire, including magnet wire (24 AWG, $16/lb.), stainless steel wire, and brass wire. The small flyer that they sent me also shows all different types of plastic, rubber, bearings, gears, belts, mesh, tubes, and fasteners. Very cool!