Since 9/11 many photographers have complained about being harassed while photographing buildings (federal and otherwise) in the U.S., and now there appears to be vindication for them: the excellent Lens blog from the NYT has published a document from Homeland Security stating explicitly that it’s legal for photographers to photograph public buildings in public spaces.
On a related note, I was surprised about this legal finding from last August—apparently property releases aren’t always needed after all, when photographs of buildings are used in advertisements (as long as trademarks aren’t visible). (I’m no lawyer though, so be sure to consult one if you’re selling pictures of buildings for ad use. Here’s an attorney specializing in photography-related issues.)
Update: Rohn Engh over at Black Star Rising is adamant that when selling a photograph of a person for editorial (as opposed to advertising use, or some kind of product endorsement) use, a model release is not needed. Here’s the post.