Travel reservation site Expedia starting working on its Expedia API back in 2009, according to the changelog. It has three APIs, covering hotels, flights and cars. Don't be shy. Expedia has been expecting you. The Expedia developer site has all the warmth and care of a fine bed and breakfast. They clearly want to invite you in, make you comfortable, and get your development project of the ground. Though they do have a couple hoops to jump through, as well.
Infradox serves up your archive of photo and video on a high volume basis. The Infradox API is actually two APIs: a "Partner API" and a "Back Office API." The partner API is, not surprisingly, for your partners so that they can connect live with your Infradox database. Responses are in XML.