I've found it harder to align horizontals with K20D than with my Canon F1s...
...I've proved to my satisfaction that this is not a camera error... something about the viewfinder makes it easy to be sloppy...
MAYBE a grid screen will help...I want one eventually and one of my Canons has always worn one...
...HOWEVER I've just realized that I didn't have the viewfinder diopter perfectly adjusted...check that out..it's a well-designed Pentax standard feature... I'd overlooked it...should be helpful for everybody with iffy un-corrected vision, glasses, or contacts...
...we're probably all aware that alignment with horizontals is harder with wide lenses than with long lenses, right?