There are many sites with games. To your list, I would add Le Grenier du Mac (The Mac Attic). There are many classic games there, as well as apps and utilities galore.

And as an additional source of URLs to check out, see Gamba's site, home.earthlink.net/~gamba2. He provides an extensive set of links to other sites. It hasn't been updated in a couple of years (Gamba is sadly no longer with us), but many of the links are still good.