The new Sony RX100 (yes, one more "X" camera, very trendy) is bound to get interest from enthusiasts. In short, it's very much like the popular high-end compact Canon S100, only slightly bigger, and with a much bigger sensor. Extensive review here (the review has an interesting test-image comparison of several compact cameras at different ISO speeds). This is a real compact, a bit larger and rather thicker than the S100, but still shirt-pocket sized. (Note: the S100 is really small.) It's not cheap though, about $650, almost twice the price of the Canon. That's a serious price, but then it has some serious advantages per reviews.
It improves on the Canon not only in sensor size, but also in autofocus speed. It has always been a problem of really compact cameras that the AF was much slower than bigger ones. The S100 has around a half-second focus lag, which is a lot when shooting moving subjects. The RX100 cuts this down to a quarter second in tele mode and 1/8th second in wideangle mode, which is really good.
This must be the first real pocket cam (the Fuji X10 is barely one) which can shoot pretty much useable quality at ISO 6400. (Notice that it has the ridic resolution of 20 megapixels, so artefacts will appear worse than they are, viewed at 100%.)
Even though Canon S100 is one of the best pocket cams around, the test images show a clear advantage to the RX100 in terms of resolution even at base ISO, showing that the hard work to mash in the biggest possible sensor in this small body has paid off.