Thanks for starting this club. A great idea.
I have been a Pentax user since 1975 (SP1000 & Spotmatic SP) and the K10D was my first K-mount. I had been waiting for Pentax to produce a camera that met the specs I was waiting for. The K10D was that camera. I bought one and I have never looked back.
When you learn how to get the best out of it, it produces fine images. Sure, I would like a K-5iiS or a K-3 but, as a retired person, I find it hard to justify upgrading while my K10D is working as well as it is.
Fortunately, the 18-55mm kit lens is regarded as one of the best and that is good because I have taken most of my images with it. The zoom range just suits me. I have upgraded to the WR version.
Here are a few of my images to showcase what the K10D can do:
There are plenty more on Flickr.