Why did I get a D300?
-Spot metering. Big for me, as is the very reliable 3d matrix metering. I never liked the 20d's meter and often found myself using exposure compensation on every shoot. Flash Exposure Compensation is even more off. VERY happy with the D300 metering so far, tho I do not have a SB-800 yet. White Balance is also more flexible and accurate tho indoors its still dicey.
-Live View. Will be cool for precise focus checking especially on tripod mounted macro shoots. Maybe for over the head two arms extended shots too.
-A true pro AF system. It's the same AF as in the amazing D3. I have been consistantly frustrated with the 20D AF. There is so much to learn in this new system and choices for different situations that it's still too early to make a call, but I was moderately happy with the speed it kept up with buzzards in flight yesterday.
-The 3" LCD is a game changer.
-2.5x the FPS isn't huge for me but could open new doors for my soccer pics.
-More megapixels is not a big deal, certainly wasn't something I would have paid more for. Requires more space to burn the files but also allows more detailed crops when needed.
-The 18-200 VR is a FUN lens. It's not a professional lens by any stretch but it's got a lot of uses for walkabouts and family events. Convenience and light weight with no equal on the canon side.
-Fun stuff: Built in intervalometer and multiple exposure mode. First I will use a LOT, second not so much but still fun to play with.
-ISO 6400. Huge for me if it matches the hype. Not expecting D3 like results but still nice to have and also never get antsy about using ISO 1600 and beyond.
-All my old Nikkors now fit =) 50 1.8 is fun and light and bright and easy to hand to a family member.
Plus as noted I'm KEEPING the 20D and my best lenses =) I still admire what Canon puts out, but at this time they are a big step behind in the market that I fit into and the new features I value most. If they had put an AF system like the D300s and an LCD to match in the 40D it might have been a lot harder to make this jump, and I'm going to have my eye out for what comes next for the 5D class bodies. It's going to need to be huuuuge to convince me that I need that more than I need better glass.
I knew the 18-200 would have a bit of Chromatic Aberration, Lr looks like it will clear that up if it really bothers me. What I really wasnt expecting was how much it vignettes at 200. Doesn't really bother me since its easily correctable but I was shocked nobody mentioned it in any of the reviews I've read.
I had been led to believe that Lr and Nikon weren't really playing nice together but so far I have no complaints other than the monstrous NEFs take a lot longer to be processed by my aging rig than the svelte 8 megapixel 20D raws. =) I'm not giving up on Canon totally, I love the 20D and its now my backup cam and am keeping my best lenses and selling off some lesser pieces. Once a real successor to the 5D comes down the pike I might head that way again but I have a feeling the D300s gonna keep me happy for a long long time.