Best medium leveled Nikon DSLR camera for me?

I have the nikon d3100 and i love it, but now i feel the need to upgrade since i've controlled all the uses for it and I understand camera concepts, photography concepts etc etc. Its been 2-3 years with my nikon d3100, and now i want to upgrade!

any suggestions?
(NIKON ONLY Please since i only have nikon lenses and accessories etc)

price limit is under $2, 000:) thanks
and recommendations for lenses? Your favourite lens? Thanks in advance!

Added (1). When is the d400 coming out and how much is it gonna be around?

At present, that would be the D7000. The D5100 is still an entry level camera.

Later this year, the D400 should be announced, and possibly a replacement for the D7000 - so depending on your time frame, you may want to consider those as well.

The D7000 is a great choice

The most used lens is the 24-70 mm f/2.8 lens.

It and the D7000 should just meet your budget of $2, 000

Is there something you need on a higher end model? Is your camera dying|? If not, best would be to buy more Nikon lenses which will impact your photography so much more than buying a new camera body

if you must, however, I second either the D7000 or wait until the D400

I have a list of the best Nikon cameras out now:

http://www.amazon.com/...zon.com/s/

Out of these i recommend Nikon D300s 12.3MP CMOS Digital SLR Camera with AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II Lens:

http://www.amazon.com/...002JCSV7G/

Its features are:

-12.3-megapixel CMOS image sensor for high resolution, low-noise images3
-Includes AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II lens
-Nikon EXPEED image processing; D-Movie HD Video for cinematic 24 fps, 720p HD movie clips
-3-inch Super-density 920, 000-dot VGA LCD; one-button Live View
-Capture images to SD/SDHC memory cards

Read this review by a user about the overall performance of the camera:

http://www.amazon.com/...218M9RUE4/