I'm brand new here but I saw this thread and I had to put in my two cents. My wife and I have been making a fair bit of money lately shooting weddings. We have two Pentax K10D's at our disposal and they are fantastic cameras, the Pentax K10D is the top of the line from Pentax (until January), and it is definately a pro oriented camera.
The reason why I mention it is that this camera is about to be upgraded, and because of this it can be had with an 18-55 mm lens for about $640 at
http://www.adorama.com and elsewhere. I can't recommend this camera enough, it is a stunning performer especially for the price.
In late 2006/early 2007 the K10D hit the market and made Canon and Nikon look silly for charging $1,500+ for a similar camera. That's Pentax's traditional business model: provide a high quality product for far less money and be content with not selling boatloads of cameras. Yeah they aren't that well known (these days) but they make the best products for the money out there.
Let me list to you why I'd pick a Pentax K10D over any other camera right now, admittedly this is my list and you may have different ideas about what you need:
Weather sealed body: The K10D is sealed with no fewer than 70 gaskets to keep water and environmental contaminates from contacting it's inner workings. You won't find this in a Canon for anywhere near the price, and you have to but a Nikon D200 at least to get weather sealing from them.
Built in shake reduction: The Pentax K10D has a shake reduction feature built into the camera body that will give you an average of two stops worth of shutter speed slowdown. It works with every lens you attach to the camera. Nikon and Canon have a lens based system that has been shown to be more effective in lab tests but that you have to pay for separately with every lens. It's usually about $100 or more in additional cost to get their shake reduction lenses.
Lack of pre-set scene modes: The K10D leaves "sports mode" and "landscape mode" etc out of the cameras control nob. This leaves room for a shutter-aperture priority mode where you select the shutter speed/aperture combination and the camera adjusts ISO to make it happen for you. It also has a sensitivity priority mode which will allow you to select the ISO setting and the camera does the rest. These are two features you won't find on any other DSLR anywhere.
Compatibility with every K-mount lens ever made: The K10D will work with any K-mount optic you can find. There have been over 25-million made to date, and that's just the ones made by Pentax themselves. Canon and Nikon haven't shown even a resemblance of the level of customer concern and loyalty that Pentax have shown in this regard. You can find K-mount lenses anywhere and for cheap.
Support for SDM lenses: The K10D supports Pentax's SDM focus motor system which places the focusing motor in the body of the lens rather than the camera body it's self. That way you can use the newest offerings they have as well as the older ones. The Pentax K100D that someone else mentioned earlier does not support SDM lenses. The K100D "super" does however.
I could go on and on but I'll leave it at that lest I bore you even further. I think that you are in a unique position to pick up a truly professional leve DSLR for an amature's price right now with the Pentax K10D, and like was stated before, if it doesn't pan out for you in the future, you won't be so far in that switching becomes prohibitively expensive. I know however; if you do pick Pentax, you won't be wanting to switch.
SLC
