Replying to Purchasing My First Camera

Hey guys. I'm sure most of you don't want to see another "what kind of camera should I get" thread, but I don't feel like search barring for a thread is going to meet my needs. It'd be hard to find a thread that specifically is going to fit my needs.

So anyways, I want to buy my first DSLR Camera. I've taken many pictures, that my friends consider to be outstanding, but with a Point-And-Shoot. So I want to step it up a notch and get something of quality.
My main areas of interest for photography are nature/landscapes, and skiing of course.

I guess another question is; what's wrong with Fujifilm, Pentax, Sony, or Olympus? It seems to me like Canon and Nikon are the ways to go, but why?

My price range is anything under 650$. I don't want to spend a whole lot of money on my first camera. And yes, I do know that extra lenses and what not are going to cost a pretty penny as well.

And basically, what are some tips you'd like to give to a new photographer?


Thank you very much!!