Originally Posted by Groucho 
That's a very unfair comparison. Not only the 50mm F1.4 vs F1.8 (the Canon F1.8 certainly can't compete with the Pentax 1.4 on any level), but an F4 long zoom vs an F2.8 one? Two third-party lenses for Canon vs zero for Pentax? And to be completely fair, you'd need all IS lenses on the Canon side - which means no 50mm and not the Tokina 16-50mm.
You can work prices any way you want and you can certainly build a K20D system for the same or less than a comparable 40D.
You have to consider that I am not a canon dealer I just was putting an example of what I think that it is a compelling equipment for both brands with similar quality. As Aegispan mentioned you can change the 50 1.8 for the 50 f1.4 and the price will match. I was using 3rd party lens that are rebranded pentax to match the quality of the lens (add the 50-135 if you want). The canon 70-200 f4 (for what I have seen, not my experience) is an extraordinary lens that match or exceed the 50-135 in every single aspect (from f4). I am not trying to convice you or anybody to go canon or nikon or whatever, I am just pointing out that besides the old lens compatibility, Pentax is not a bargain anymore. Again, Pentax has now a much better system that it has before (particularly with the next arrival of long new 3rd party lenses) but some of the extra stars that it had before are not shinning anymore. THe IQ from both cameras, which it is the point of the OP is a mixed bag with some good things in 40d and some other good things in K20D. I brought all this price comparison stuff to answer what I think that it is a wrong concept of some posters here that consider Pentax as the best bang for the buck. I am just saying that they should justify their decission on other aspects, period. I feel quite comfortable owning Pentax and knowing that other brands have other products that are better in some aspects than mine. I just dont get why some people cannot accept that and has to criticize whatever Nikon or Canon does.