Ultimately most of the suggestions posted are still based on user reviews so it is ultimately trusting someone else.
The best thing that you can do is read reviews, listen to opinions, then taking that feedback as information and with a unbiased frame of mind, go inspect and handle the cameras yourself.
It is hard, yes. Most humans end up with a bias one way or another.
Ultimately you have to take it, feel it, like it before buying it.
However, do consider my points of thought:
Canon is vastly more popular as you can see... but true, it's expensive. Most of the price goes into marketing. However the penetration means that you have more other photographers that you can borrow lenses to test test and try try. Join any photoshoot and see for yourself the rarity of Pentax.
That said, I am quite partial to the Canon interface system with the in-eyepiece information (that was the selling point for canon over nikon in the end for me).
However, go do your research on Pentax also. They may not be well advertised, but they are really old timers in the camera arena. Check out their range of lenses and whatnot, whatever that Canon can give the average photographer, pentax can offer at a much lower cost and quality is solid. The builds for Pentax cameras is generally more rugged, and they try to squeeze in more dings and whistles, however I still cringe at their menus and handling system.
Think then about support and servicing, as well as ease of getting parts. The more suppliers means more competitors, that also translates into bargaining power.
Don't write off Pentax, but don't dive into either one too quickly either. Buying a DSLR is like choosing the field of study in university... you are stuck in that field for your life, unless you have the funds to change course and/or diversify.
Just my few cents, I'm sure the above has been mentioned earlier buy others somewhere sometime ago.
Cheers.
