Adrian 3 bits of advice , well three come to mind ,
1.Read all the reviews you can find on both k10 and the kx, look at the features controls, viewfinder displays and other displays and so one and compare to your current body. You will begin subconsciously start to get a favourite start to come to mind.
2 now go a shop and hold them both , turn them round;feel it,squeeze it; weigh it;and play shooting both models and see which one feels right , believe me one will. [assuming the shop has a k10 if not try a k20] if there is A K 10 there put a card in both shoot a pile of shots in out of the shop . if you are still aren't sure sure put a refundable deposit down, if needs be, go home and look at the images. be sure you tried to use the same settings and subjects.
3 most important do not listen to anyone but your heart.!! no one but you knows what is best for you. no one can probably tell you any more than the reviews have.
this last one will cause some shots accross my bows I suspect but its like your tastes in other things in life it's you who have to live with the choice [ if you love that blue tie with pink spots and elephants on it wear, to h**l with them all!!
Alistair
ex k100d owner which I realy enjoyed and now a very happy k10 d owner