For this same planned use (well, primarily bike touring) I bought an XZ-1 -- but it's too big and heavy, and I can't really fit it in a pocket, and I find I don't carry it with me enough. (Anyone want a lightly used XZ-1?)
I considered the S95 (but I wanted 24mm) and the S100 (but so expensive!) and ended up with the ELPH 300HS. CHDK (alpha) is now available, so you can do star trails and more (and CHDK gives you plenty to play with!). The image quality is quite good, even at low light, although not quite S100-level.
Best of all, the 300HS is tiny , and I can carry it in any pocket at any time. And at $150, I don't have to baby it like I would a $400 S100.
Just my 2c.