...aside from Emaculation and the Macintosh Garden...and YouTube...
The Cutting Room Floor
is perhaps one of my most visited places as of now. It's a site detailing all the unused stuff developers left behind in their games, changes between regions, and prototypes of a few video games.
Granted, there are a lot of little things missing that people have yet to discover and the activities involved are dubious in legality, at the least. However, for what it is, it certainly is pretty good compared to a lot of other sites.