I have gone from K1000 to k100d (via a few P&S) and now upgaded to the K20d. I liked the specifications of the pentax. I learn more about it each time I use it, it is a camera that has the right 'feel' for me. I have handled some of the other brands, but keep coming back to the 20. I do not upgrade with every new model and feel that this is a camera that will be with me for some time to come.
When the K10 was released, I had itchy feet and wanted to get one, but didn't. Now I have the k20d, I am more than content to stay with it. So mine wont be up for sale