Thanks fengwei! Actually I am in abit of a dilemma here. I am currently using the GF1. Quite happy with it except for its high ISO performance. I only came to know of the K-X last week but after seeing many sample pictures online and the pictures you posted on the comparison between the K7 and KX, I am sold! I really like the colour of the photos and its ISO performance. But I am abit hesitant because I do not want to carry a big DSLR around. I used to own a Nikon D80 but sold it off because I find it too heavy and bulky. I got the GF1 and in terms of size, it definitely fulfills what I want. I know the KX cannot compare with the GF1 in terms of size but I hope it will at least be smaller than the E450.
Here is the size comparison:
K-x: 123 x 92 x 68 mm
500D: 129 x 98 x 62 mm
E450: 130 x 91 x 53 mm
Hope you get the idea about how small Kx is. Kx is narrower but thicker, its grip feels the best. Of course this is a personal thing, better try it in store if you can. I think you should be able to try the camera at CP/OP/MS Color. Or just get a Km and see how you feel about it. Km and Kx are pretty much the same camera on the outside. But inside they are quite different.