My answer is based on the way I might use a D7000 if I added it to my bag.
The reason I figure it would be good for covering wide shots and detail shots is more of a personal thing... just how I'd use it if it were a second camera along with my D300. This is because the D300 is a known commodity for fast AF for sports (cycling, for example) which I'd use my longer lenses on, and also the quicker handling/settings changes (because of more external controls available on the body) while the camera is in action and I'm looking through the viewfinder. For more deliberate shots and wider angle (background shots, behind-the-scenes, detail and environmental portrait type shots) where AF speed isn't as critical, the higher resolution of the D7000 would make it a decent companion body for those kinds of shots. I'd likely use each camera for it's particular strengths in handling.
So, I'd probably keep the 80-200 on the D300 most of the time, and a wide-angle or 17-55 on the D7000. This would result in fewer lens changes, since I'm working right now with only one body in the field...
Having said all that..., given the choice I'd probably stick with a second D300 or D300s for the reasons I mentioned above (controls/batteries/CF cards, etc..) The D7000 controls/configuration is still basically a D90, and I might find it less enjoyable and inconsistent to adjust things on the fly compared to what I'm already used to. It's an interesting camera, nonetheless, because of it's potential IQ performance and 1080p video. If the dust resistance and weatherproofing was equivalent to the D300, it would be a tough call between them since I already have a D300. No contest, however, if I can only use one -- D300 still fills the bill for me, and I wouldn't trade it.