http://www.plan59.com 50's era marketing
http://www.shorpy.com historical photos. This is also an interesting business model. The content is just free for the taking from public domain sources.
http://www.on-my-desk.blogspot.com A look at lots of designers' workspaces. Mine is amazingly bland, mostly because I don't do a lot of design work anymore, but also because I have kids around that steal every cool toy or inspirational clipping. In exchange I get to look at their odd liger-ish animal drawings and a parade of stuffed animals in all the latest paper and tape fashions.