Explore your options...
With any new DSLR you get will have RAW option, so that is no problem.
I agree with some others here in that the quality of lens is important. Good lenses tend to keep their value over time and can be used for newer bodies -- so most DSLR users keep their lens collection that is suited to their style of photography while selling/updating the bodies when more advanced ones come out.
Of course, for the best image quality and dynamic range then probably your obvious choices are Canon or Nikon. But there are also other factors too which maybe important to you, so the more research you do and the clearer your criteria/s the better your choice will be.
For me, I have just recently sold my DSLR Canon Rebel XT and Canon Point-and-Shoot because I wanted something with the image quality of a DSLR but with more portability -- something that I can take around with me anywhere to take good quality images without being a heavy burden. So I am very excited by the newly released 10MB Olympus E-420 (soon released in US in May) which is marketed as the smallest DSLR in the world (very light too). There is also a very thin and light lens you can get with it (25mm Pancake Lens). Just ordered them both so I am just patiently waiting for it to arrive
. I have been doing my research and another key point for me to switch to Olympus is that they have some award-winning (Zuiko) lenses -- some of the best in the industry. So I am looking to spend more on some quality lenses while the body is quite cheap. Have a look if you’re interested in exploring outside the big two.
About megapixels, it is not so important these days. Any new-ish DSLR will have more than enough MP for your needs. Even my old Canon Rebel which was 2-3 years old had 8MP and that was more than enough.
Some questions to ask yourself:
• Do you want the best image quality?
• Do you want the most accurate colour?
• Do you want the smallest and lightest?
• Do you want Image Stabilisation?
• What style of photography do you do and what kind of lenses do you need?
• Do you want Live View (shooting from LCD like on a P&S)?
• Are you on a budget and on the lookout for the best value?
Some brands are leaders in some areas and weak in others, so it is not always so clear cut what DSLR is best for you, unless you know what is most important to your needs.
Try them out for a feel in your hands (with a variety of lenses on the body). Also explore how intuitive the menu is. A key point I think is that it is something you would want to 'love' using and have with you during your variety of photo opportunities.
Anyway, happy DSLR hunting!