If you decide to go with a DSLR, in my opinion, the choices are much more limited. Canon and Nikon have long been the dominant manufacturers for these cameras. That is not to say that they are “better” than Sony, Panasonic, or any other brand. I would consider Canon or Nikon exclusively for one reason: availability of lenses and accessories. Since these companies have been around so long, and controlled a large market share, their accessories are much easier to find in camera stores, on-line retailers, and on Craig’s List. I have always used Nikon DSLRs for one simple reason: I owned Nikon 35mm SLRs for many years, and I have a sizeable investment in Nikon lenses. If I were to do it all over, I might start with the Canon SX30IS and see if I really need more capability or not. If I did, I would certainly give close consideration to Canon products as well as Nikon.
My present “go to” camera is the Nikon D7000. I have been very pleased with its ability to handle high ISO settings as well as its ability to focus my 80-400mm lens quickly. Here is a review of this model by Ken Rockwell:
http://www.kenrockwell.com/nikon/d7000.htm
If you are thinking about a camera purchase, I hope this article has given you enough information to help narrow your choice. Just remember that no matter what camera you decide to buy, you will need to invest the time to learn to use it in order to realize the full potential of your investment.