Please excuse the misc commentary but I find these types of reviews helpful if I can understand where the reviewer is coming from.
Moved from a D200, 17-55, 28-70, 18-200 to the D300, 24-70, 18-200. I really liked the 17-55 but found the tele reach just a little too short. I like the 28-70 but it was so heavy and the wide end was almost but not quite wide enough. When I upgraded to the D300 I re-bought the 18-200 for a light travel lens and I'm filling the pro end with a 70-200 2.8 VR (I had the Canon 70-200 2.8 IS and I miss it). I took a chance that the 24-70 2.8 would hit my sweet spot. What a great decision that was. I don't miss the 17-55 at all.
The 24-70 is an incredible lens. From a sharpness perspective, it's sharper than the 17-55 and wide open it's even sharper than my previous little champ the 50mm 1.8. Autofocus is incredible. It's so quiet that at first I thought it wasn't working but a check in the viewfinder confirmed it works absolutely perfect.
The lens is still a little heavy like the 28-70 but the barrel diameter is smaller so it just feels better in my hand. The front element still protrudes somewhat on tele (unlike those where all the lens movement remains hidden) but it's not bad. On my D300 I get a full frame equivalent 36-105 (as opposed to the old 28-70's 42-105) and for me it's perfect.
The fact that this is not a DX lens makes it a bonus if you believe like I do that eventually, everything will move to full frame. Lastly, if I do decide that I want more wide, I'll get the 12-24, but I honestly doubt it will come to that. If you think the D300 and D3 were incredible camera's you are in for an equally big surprise when you see what a great lens the 24-70 2.8 is.