Here are some interesting photo pools and sets I found recently on flickr, all featuring cool old buildings and signage, much of it of the vanishing variety:

First, Tom Baddley's Lost Tulsa, which we've commended to you before. He has a new set devoted to the soon-to-disappear Metro Diner.

Las Vegas History: Old photos and postcards, then-and-now pictures of casinos, motels, and other places which have or will likely soon succumb to the bulldozer.

The Vanished photo pool: That's where I found the photo of the Las Vegas Union Pacific Depot which is shown below.

The Googie, Anyone photo pool, devoted to flamboyant mid-20th-century architecture and signage.