Mike,
those are good cameras. My brother is a professional photographer in New York. He used to work at a big camera store in Boston called Levine's. he worked the rental counter which is where all the pro's coming into town for photoshoots go..(cheaper to rent than to ship your own gear in many cases), he said that this is one of the best camera's out there for a non SLR type. For the Record he's a Canon advocate and loves his Canon film camera (Elan IIe). I have a Canon film camera as well (Elan 7E), and I love it. However since I have a decent amount of money invested in my Canon gear it would make no sense to switch to Nikon for me, since none of my Canon stuff, (Lenses, Flash etc) would work on a Nikon.
There are really 3 kinds of Photographers...those who swear by Canon, Those who swear by Nikon, and everyone else. Its just like Skimmers, everyone has a preference and the difference between the high end models is really very little....They might do it differently, but the end result is the same.
You'll be fine with what ever you choose...
Altho Sony just came out w/ a new one that is 8 megapixels, 28-290 zoom, pretty fast aperture, (2.8 I think) and nighttime capability...ie IR illumination....
I'm not giant Sony Camera fan...but thats pretty cool, especially for nightime reef shots...even tho it only takes nightshots in the green common to Night Vision Devices everywhere....
Still.....
Nick