I dunno really. To me they are all just black boxes and all the same in many ways, but there's stuff about it that seems serious. Better built than a 5D, more illogically laid out but everything is available right away, instantly, and with more options. The prism and viewfinder are quite impressive, it handles well and fits your hand well, it's just a nice camera. I know it's supposed to be a D300 with a bigger chip but there are subtle differences on top of that and for me it seems to tip it over the edge. In comparison a 5D just seems like a tappy plastic toy with a gutsy sensor inside to compensate. I dunno what the images off a D700 are like, but if they're as good as a 5D or more, then it's just plain and simple, a better camera.
The SB900 seems equally so. Supplied filters in the box to alter colour balance for white balances, wider range of coverage to match the zoom lenses, no +/- buttons to up power and compensate, just a very well built turny wheel thing like on the back of new Ixus cameras. It's bigger than any other flash though. Oooh, it also apparently has a cut out which stops it firing before the flash has had time to recycle. Firmware updatable via D700/D3 too. Infinitely better flash than anything Canon do. (But then they always were.)
If you add to that the look of the new LX3 Panasonic compact which seems to answer the whole wish list for a G10 then Canon need to pull their finger out frankly.
God, I'll stop now, I actually sound like a gear nerd and I feel polluted. I shall talk about cars and breasts for the rest of the night to cleanse myself.
*I actually still really do care very little for the gear side of things, it's not what makes pictures* 