I bought a kx about 18 months ago, and loved it so much that I used my tax rebate before Christmas last year to buy a k5, and I've also got an auto 110.
Boris, you'll love the upgrade, the k5 is so much easier and more intuitive, and the obvious things like twin e-dials, superior low-light sensitivity, and best of all, tav will blow you away. The kx is an incredibly capable camera and I can't see myself ever selling mine, but when you first pick up your new camera and feel how solid it is you'll fall in love. I did rather worry my mates when I first got mine by saying that, if it had an orifice, I'd marry it