+1... I have the s90 - it is very good, and (from everything that I've read) the s95 and s100 versions have gradually refined out most of the minor items that were 'wrong' with the s90.
In digital, it's difficult to find anything that has as much functionality and quality as the Powershot 's' series, at a size which will fit
comfortably into a shirt pocket or trouser pocket. You might get suggestions for other compact cameras which can equal or surpass these in functionality, but I doubt that any would be as small.
You didn't state whether you were asking for digital only, but outside the digital realm, the Olympus XA would be an option - provided that you can find one in good order.