For general parts (logic, memory, sockets, breadboarding materials and tools, etc.), I've used
Jameco a lot, as well as
Digi-Key and
Mouser, and to a lesser extent,
Allied Electronics,
Newark Electronics,
Debco, and
JDR Microdevices. The last two are smaller distributors.
Jameco's paper catalog is more convenient to find things in partly just because it's not so big, and yet they have vastly more than Radio Shack does and for a fraction of the cost. Digi-Key has more variations of more specialty ICs than you can shake a stick at. It seems like if they only had one of everything in the catalog, the warehouse would be huge-- and yet they stock hundreds or even thousands of each. This makes for great availability, but the prices are a bit higher. Mouser seems to have a bit less in the area of ICs than Digi-Key but more of other things. Newark's website is kind of hard to use, but it gives another place to find things. Allied is good and I do prefer it over Newark, but it's not one of my favorites.
To give you an idea of how much these places have, Digi-Key's and Mouser's paper catalogs are each about 2,000 pages of fine print, and they have nearly all of it in stock. Newark's and Allied's are the same size, but not so fine-print. Jameco is a little more hobbyist-oriented having a smaller catalog with a higher percentage of thru-hole (as opposed to surface-mount) parts, although you don't have to be in the industry to also take advantage of the big ones.
For the 65cxx parts, you can go straight to the source,
Western Design Center or buy them from Mike here on this website. Many people don't realize the 65c02 and 65c22 are in production today at WDC and they plan to continue indefinitely.