The governments of Saudi Arabia and the United States Air Force have fitted 757s for VIP transport duties (see C-32), and at least one is in use as a private aircraft (that of Microsoft co-founder Paul Allen). Presidential challenger John Kerry used a chartered 757-200, nicknamed "Freedom Bird," during the 2004 U.S. presidential campaign. The Royal New Zealand Air Force RNZAF has two that are used for transporting troops and VIPs. A 757 is also serving as the Presidential Transport in Argentina.
Cam adds: let me just say that the 757 is pretty much the most boring airplane ever, at least according to wikipedia. I hope that ten posts from now I have something more fun to copy and paste. :)
* Due to some back-posting of Toronto Pride misadventures from the late 90s, this is actually post 758. Oops!