Is the Nikon D7000 really worth double the price of the Nikon D3100?

Please only answer if you know.

are the extra do-dads that you get with the D7000 really worth twice as much as the D3100 is worth?

It matters if you are a beginner or not. The D7000 has pretty much all the bells and whistles that the D3100 has, except it has more buttons that do more things. The price difference comes in when you look at the quality of the product. The D7000 is super well-built, has an AF motor, and it actually out-performs Nikon's current semipro camera, the D300s in many areas.

The D7000 is a popular camera, one of the best cameras you can get at the moment.

as for if it is worth it or not. Have you had experience? If not, the D3100 would be a better choice because you can spend the rest of the money on lenses and other accessories. For me, the D7000 would be best, because I have lenses I can use, I have bags I can use, etc.

If you need the extra functionality that the D7000 gives you, then yes. If you don't need the extra stuff, then it is not worth the extra price.

The D7000 is not for beginners. The functionality is a halfway house between that of an entry-level model and a pro DSLR. Personally, I'd recommend getting the D3100 for now, and graduating to the D7000 later on, once you've learnt how to use an DSLR manually. Even if you are familiar with film SLRs, the functionality is very different, so I'd recommend the lower model still.

SLRs are like cars, if you try to learn to drive an F1 before a normal car, you'll just stall. Getting a high-level camera first will just mean that you stall.

In answer to your main question, yes it is, but only if you know how to use it properly.

Probably.