Buying D-SLR is actually buying a system, usually the camera body, a few lenses, and a bunch of accessories depending on your needs.
So one should spend no more than half the budget on the camera body, so that there is money to spend on lenses, external bounce flash and other accessories. I spent less than 1/3 of the budget on the camera bodies.
For $1000, this is really not much for a D-SLR system. If your budget is flexible with possibility to spend more in the future to buy more lenses and accessories, then you can spend more on the camera body now but expect your final budget to be about double of what you spent on your current camera body. Some people may think that they only need one or two lenses, and just use the pop-up flash. Well, these people are not getting the most out of using a D-SLR. So it depends on what you need and want.
For the budget minded buyer, Pentax K-x has good values but its performance is not as fast as the higher end models of Canon and Nikon. But obviously you will spend a lot more on the higher end Canon and Nikon to get that better performance. The Pentax D-SLR has good image quality, on par with the Canon and Nikon entry level models. If you have plans to do some fast action or sports photography, then you may want to consider spending more money on a Canon or Nikon (but you may end up spending hundreds or thousands more). You can get the Pentax Kx with an 18-55mm kit lens for just a little over $500, with money left over to buy a tele, an external bounce flash and perhaps even a bright lens for low light photography.