That's why it is so good to have you here. A variety of opinions is a very good thing to have.
Why thank you, I appreciate that. I enjoy being here and try to be fair in my comments on matters like this.
This is quite possibly the case when someone decides to take up a career in photography. For some, however, photography becomes and increasingly hobby and they slowly evolve towards better gear. I have mostly pro-gear now and did so by steadily changing out consumer pieces for pro pieces.
I will admit that this consideration is pretty small. Very few Rebel XTi buyers are going to wind up with 1 series cameras. For those on that path, however, I still believe that extra breadth and depth Canon and Nikon's offerings is a benefit.
Well, I think there are enough other variables that make it a fairly even playing field (or even tilted towards Pentax, as I unsurprisingly feel.

)
Two big ones:
1. Primes. Pentax has a line-up of primes that can't be beat. And as anyone who has used primes versus zooms can tell you, primes can almost always beat zooms for image quality, as well as being relatively small and fast.
2. Image stabilization. A C/N owner who decides that they want image stabilization is looking at a very significant investment in cost to do so, and they'll only get it on one single lens, and they better hope that they don't end up not liking the lens for whatever reason, or not using it much. The Pentax owner either already has it or can upgrade for a reasonable price. I could buy an actual K100D camera for, I believe, less than the cheapest C/N IS lens, still have my existing camera body, and have IS on
every lens I own and
every lens I ever put on the camera.
Those are important features, IMHO - the first to the more serious photographer who is interested in image quality (let's face it - a prime is built for image quality, an 18-200mm or 28-300mm is built for convenience) and the latter to just about everyone. IS is really the key technical differentiator right now, I feel - other than that, most DSLRs don't have anything significantly different than the competition.
Even for those that aren't interested in buying high end gear, the ability to borrow or rent is another factor that should be considered. I often tell people that are struggling to choose between Canon and Nikon to pick the one that their most hard-core photographer friend uses so that they can borrow their cool stuff when needed.
This is a very good point, if you know someone who'd be willing to loan you their good lens when you ask, that skews things dramatically, just like having an existing investment in lenses does.