First, I love my S110. And it works great with OS X....BUT:
Video clips are a problem because they are 'Quicktime AVI' files (whatever that means). Strangely enough these files are viewable using the Quicktime player in OS 9, but not with the Quicktime player in OS X (although I haven't checked since updating to 10.1, but I don't think that Quicktime was affected in that update). There may be some new codecs out there for Quicktime that I haven't found, but I don't think there's any way of viewing these files on your computer unless you go through OS 9.
What's more, these AVI files aren't good for much more than just viewing. I can't import them into iMovie for editing unless I convert them into raw DV format first, which is a pain. The clips are also very short, up to 30 seconds for 640x480/20fps clips if you have at least a 64Mb card (even if you have more, 30 seconds is still the limit). Audio pickup is kinda bad, but the image quality of these videos is very good considering that it came from a still camera, but not as good as a DV camcorder.
Bottomline: If video is your thing, get a video camera. Video from the S110 is really like the bear riding the bicycle; it's not that he's a great cyclist, it's just impressive that he can do it at all!