hey murph....Philosopher pretty much summed it all up very nicely I'd say. Here's my 0.02:
1. The Tokina 11-16mm is an outstanding lens for the Nikon. I have been drooling over one for a while now. It's nice and fast at f/2.8 and sharp.
2. VR will only really help you outdoors on those lenses. They do not stop down enough to be fast enough to work any where else but outside. For me, I prefer a faster lens than one with VR. Another outstanding mid-range zoom is the Nikon 17-55mm DX lens. It's big. It's expensive. It's fast. It's sharp. Basically just awesome. A lot of people like it for a day to day carry around lens. It gives you the same usable ranges as the 24-7-mm does on the FX full frame cameras.
3. I love my Manfrotto tripod. I have a 190 (there is a variety of different ones). The thing I love most about it is that the center pole can be adjusted to be horizontal / parallel to the ground. Excellent for getting in nice and close to the subject. Get a decent ball head that will support the weight of your camera and largest lens too.
4. For macro I'd get a BR-2A reversing ring for your 50 f/1.8 lens and go to town on the macro. See my posting here
One other note. If I had the money, and in your situation, this is what I would do:
Sell the 18-55, 55-200, and Sigma lenses. Buy a Tokina 11-16mm f/2.8 and a Nikon 17-55mm f/2.8 and save for a good zoom lens.