Life is crazy and fun I am actually contemplating selling my 17 TSE to finance the x100s and its various filters, flashes for it, and stuff. I was very ambitious when buying the TS lens, but with two small children I have not had time to really learn how to use the tilt and shift. Given my other lenses, I feel that I have much covered so I will not be to hard on my day to day photography.
Exactly my thoughts on the TS-E 24mm. I love shooting architecture -- which is the bread and butter of any tilt shift lens -- but with my son being born a couple weeks ago, I fear my architecture shooting days may be few and far between now.
I was also hesitant about purchasing such an expensive camera with a fixed prime lens. However, since my son was born I'm yet to break any zoom lens out of my bag. I've been exclusively using my 35mm, 50mm, 85mm, 100mm, and 135mm. I've been using my 85mm the most, as I really like the bokeh that lens produces as well as the the frame you get with the 85. BUT if I had to pick only one of these lenses and discard the rest, I would likely go with the 35mm for its versatility. So that made my decision on the x100s a little easier.