Neither, of course... honestly I wouldn't recommend either until they start putting image stabilization in the body, unless you are looking at a very high-end (like $1,500+) DSLR (and only then because nothing in that class has in-body IS - yet!)
If Pentax didn't exist, I'd probably use a Nikon (maybe a Sony), because the ergonomics of the Nikon are similar to the Pentax. Canon seems to be bought most often by people who are buying because of the Canon name/reputation rather than the camera itself (obviously there are exceptions, no need to flame!) The Canons also have a rep for iffy ergonomics, iffy build quality, and the worst kit lens. (Lest you think I hate all things Canon, we did recently buy a Canon PnS for my wife.)
Of course, they can all produce stellar image quality. That goes without saying. And with the Nikon and Pentax generally using the same sensors, it mostly comes down to lenses and software. Nikons seem to do slightly more aggressive noise reduction (Canon even more, once or twice I've heard mention of the Canons producing "plasticky" skin tones) than the Pentaxes - which you prefer is just that, a preference. But Pentax's unbeatable line of primes and history of great lenses sway me in that direction.
But again, image stabilization in the body is a huge difference for me. Every lens, no exceptions. With C/N, you'll pay, and pay dearly, every time, and too bad if you buy an IS lens that is not everything that you hoped for optically. So ultimately, unless you have an existing lens collection, I'd have to recommend the K100D for an entry-level and the K10D (with countless cutting-edge features) for a higher-line one.
But, as has been said so many times - they're all superb. We're talking about pretty fine little differences most of the time, and no matter what you get, the camera will probably be capable of better photos than you're capable of taking.