I'm a little late to this thread as well, but I can say that I purchased a 24mm Canon TS/E lens about a year ago and it has transformed my architecture business. Before, I was just doing everything through PS and it looked ok, but I was cropping out important parts of my photos. With my TS, not only do I get everything in the frame, but the quality is much more noticable. I believe that any architectural photographer who doesn't use some form of a tilt-shift lens is really missing out. There are certian pieces of gear needed for this type of photography, and a TS lens is at the top of the list.
Regards,
David Massengill Architectural Photography