I agree with those who advise using Nikon brand batteries. If for no other reason, there is the following statement on page xvii of the D7000 User's Manual regarding the warranty:

"The use of non-Nikon electronic accessories could damage the camera and may void your Nikon warranty. The use of third-party rechargeable Li-ion batteries not bearing the Nikon holographic seal shown at right could interfere with normal operation of the camera or result in the batteries overheating, igniting, rupturing, or leaking."

Rocky