I'm a K20 user that has recently moved from Alaska to Utah. I just signed up before I left but haven't had any time to read the forum. Hopefully I'll get past the house buying and moving in drama and be able to focus on photography again.
I was a K10D owner but upgraded and do not regret it at all... huge difference in camera. My favorite lenses are:
Portraits - Pentax 50-135 f2.8 - has no equal.
Overall use - Sigma 18-50 EX f2.8 - great lens, quiet, responsive, reliable.. super clear.
Landscapes, cramped interiors - Sigma 10-20 EX f4.0-5.6 - great lens. I find myself using WAY more than I thought I would... my only complaint is that I wish it was a f4.0 fixed rather than f4-5.6
Live stage, sports, wildlife - Sigma 100-300 EX f4.0. It is a beast, but it brings them in and it is fast and quiet.
Well, I'll post more later sometime.
John