It sells for SEK2900 in Sweden, which is about £200. I think I have seen prices around US$300 as well. Not really cheap, but probably a fair price.
My girlfriend, my sister, and one of my friends have Dimage Xg:s (one of each color), and it is just a lovely little camera. I have also tried an X50 (or perhaps an X60, can't remember), which was just as lovely. It is really small, starts up quickly, and takes good pictures for a camera of its size. I do not think the X1 has done anything but improved on earlier models (X,Xi,Xt,Xg,X50,X60), with the AS being the most notable difference.
The design of this series of cameras is excellent. Having the lens inside the body with a mirror does two good things: The camera starts up much quicker since it does not have to extend the lens, and it is much more resistant to sand, dust, and violence (the extended lens is the weak spot for most other compacts).
Just as with most newer compacts, the optics in the X1 are of course nowhere near the 8MP resolution of the sensor, In the 3MP Xt, the optics are about on par with the sensor resolution (except at max zoom and/or f-stop), and it has probably not been that much improved. From the test pictures I have seen from the X1, it looks quite good anyway. The lens is good for about 3-5MP of "real picture".
I would say AS just as good a thing to have in a compact as in a larger camera, if not even better. Compacts usually have fairly bad f-stop values and not that high ISO settings (and if they do, they are horribly noisy). The AS, and my good experiences with earlier models, is enough that if I were to buy a compact digital camera, I would get a black X1 right away.
For now, I borrow my girlfriends Xg in those cases were my 7D is just to big to bring along.