Neil,
I'm not a Nikon guy but I assume the 24-70 you're referring to is the F2.8 and the 70-200 is also the F2.8 VR model. Those are very nice lenses and on a D300 will give you everything you could need certainly in the short term.

I'm not aware of any Nikon mid-range zooms with VR but if there were, that would be ideal. But the two you mention are two of the very best. Keep in mind that the combination of camera/grip and zoom lens is pretty hefty for one-hand shooting if that's your portrait style (I know; I use the Canon 5D or 30D with battery grips and the 28-135 IS) and it can be a handful after a 1/2 hour or so.

Nice choice. I hope that Julie chimes in on her E3. She gets some really nice action shots with her gear.

Jim