I'm sorry, I've heard this chestnut over and over and I just don't buy it. Especially because it is usually used as an argument against buying anything but C/N.
This idea that you are "locked" or that you will end up losing out in a huge way if you decide to switch systems just doesn't make sense.
Your average "serious" DSLR buyer is likely going to buy a new camera every couple years or so. This is the same regardless of manufacturer, so you'll take a bath whichever way you go. Comparatively, you will usually spend more for the "big names", too. Regardless, switching bodies at this point is no additional cost since you're buying a new camera anyway.
So what's left? Accessories? Well, most accessories are interchangeable between brands; the only big one that I can think of that isn't is an external flash. But c'mon - you'd probably want to upgrade to a bigger flash at some point anyway.
Also, flashes don't depreciate the way bodies do; you will get most of your money back. Buy the flash second-hand in the first place and you will likely lose nothing.
Lenses... well sure, the kit lens and related low-buck lenses won't retain value. (Again, you can buy used if you want to protect against that.) Quality lenses will retain their value or appreciate. I bought a lens in February that I just sold for more than four times what I paid for it. That is certainly not common - but I bet that out of my fairly extensive lens collection, I could sell virtually every single lens for more than I paid for it. And those cheap lenses that do depreciate? Guess what - you'd be replacing them with better lenses anyway, no matter what system you use.
Finally - the other problem that I have with this stance is that if no one buys anything except the "big 2", then of
course other lines will suffer! The industry needs more competition, not less.
Daisy14 - don't worry, take the plunge; you're not taking a risk any more than buying any DSLR. You should be able to find the K-x for $550 in a few places. We just bought our red one for $535 w/free shipping (which we upgraded to 2-day.) (Abe's of Maine, $550 minus $15 coupon. I go with them because they don't charge NYS tax unlike
Amazon; the downside is that they will make you call them so they can try to sell you a UV filter. Just say no thanks and you'll do fine.) I think that you'd have a hard time finding anything better for anywhere near that price.