As a photographer for my college's newspaper, most of what I shoot is either low light (concerts, dances, etc.) or sports, so I'm looking into getting a low-light/high speed telephoto zoom for my Nikon D7000. I already have a 35mm f/1.8 that I use for most low-light photography when I have the opportunity to get close to my subject, but I can't always get a press pass for campus events (passes are handled by individual campus clubs who don't always respond to emails), and so I often wish I had some zoom besides my kit 55-200 (from a D40 kit several years ago) that would still be clear in low-light.
I've come across two lenses by Nikon that seem to be mostly the same for my purposes: The AF 80-200mm f/2.8D ED, and the AF-S 70-200mm f/2.8G ED VR II. I ask, because there's nearly a $1300 dollar difference between them: Is there a practical difference between these two lenses?
I'm aware of the obvious technical differences, AF vs AF-S, and the lack of VR on the 80-200, but I was curious if either of these features made a practical difference in focus speed and usability. From what I understand, on my D7000, the AF vs AF-S shouldn't make a difference, but is VR really worth the extra $1300?
On a related note, I've also heard some people mention cheaper Sigma and Tamron lenses in the same focal range and aperture size, and I was curious what some of the differences would be between those and their Nikon equivalents?