It's an easy choice... Go with D90! I am using it, and loving it.
Tried a few Canon cameras a few days ago in Vivo City. Really didn't like their ergonomics. For example, for changing aperture, you need two fingers (one presses a button, the other rotates the dial)... It took me a while to figure that out. You may say it's a matter of habit. But since aperture-changing is so frequently performed, it should be designed to be as easily-performable as possible. It is certainly not the case with the Canon camera that I have tried.
I also tried Canon 550D. In addition to its poor ergonomics, it's soooo small and light... It's very much to my disliking.
So, the answer is obvious (at least to me). Grab a D90 and go hiking!!:thumbsup: