Well you have a lot of good advice here. The Nikon D40 is lightweight & inexpensive. Look here http://www.kenrockwell.com/nikon/d40.htm

Canon, Nikon, Pentax, Olympus- it's the eye behing the lens that matters most.

I have Nikon DSLR's up to D2x & D700-love'em. Sometimes take a D200 or 700 backpacking w/1 zoom. However I have a Canon 650IS which is superb for a P&S.

For image quality megapixels are misleading, look at size of sensor if you are serious. DSLR's have much larger sensors than the P&S which means less digital "noise". Also the lack of viewfinder & RAW in P&S is enuf to make ya want to tote a heavier camera. Don't forget the tripod.