Will it be worth upgrading from the Nikon D3100 to the D7000?

Will it be worth upgrading from the Nikon D3100 to the D7000?

Probably not. Most, 'Upgrades,' are by bad photographers throwing money at their problems - you run out of money long before you run out of problems.

When your D3100 croaks, then buy a new body.

The D7000 has some worthwhile additional features, but what you have is already very good. You're probably not missing many pictures for lack of a D7000. If you are getting itchy to upgrade, then it would be best to try to be patient for a few months to see what the successor to the D7000 will have.

If you have money burning a hole in your pocket, how is your tripod?

Only you can decide that.

What features does the D7000 have that the D3100 doesn't. Make a list. Do you need/want those extra features? Are they worth the cost of the upgrade?

One thing for sure if you are taking poor pictures with the D3100 then buying a D7000 will not magically make them better.

It will only be worth it if you know why exactly you are upgrading. If it's just to get a newer camera then no.