Which Nikon DSLR setup is better?

I'm torn between getting a Nikon D5100 with a tamron 70-200 2.8. Or getting a used Nikon D7000 with the 18-105 kit lens. I have used the tamron lens and really liked it. I know the D5100 has the same sensor as the 7000. I would like to do some semi pro work on the side. Portraits and candid shots. Both these setups are about the same price range at B&H Photo.

7000 will get you CLS commander which is nice for portraits.

I totally fail to see what you would want a 70-200 for portraits for

The D7000.

There's more to an advanced amateur camera like the D7000 besides the sensor; the ability to use less-expensive AF pro lenses, CLS remote commander, and a bunch of features like AI indexing that are not found on the entry level D5100.

I also agree that the D7000 would be the best choice. The D5100 does not have a built in Auto Focus Motor so it is not compatible will all of the lenses that Nikon makes where as the D7000 is. When you look into lenses, check out a couple prime lenses like the Nikon 50mm 1.8D ($150), and the Nikon 85mm 1.8 ($450). These are excellent portrait lenses.