Nikon just announced a new DSLR: the D810. What is this new camera? It's a slightly faster D800E, with a little bit lower base ISO, and the auto-focus system from the D4s. The camera will cost you $3,300 for the body.
Unless you are a sports photographer, there really isn't enough improvement here to justify buying this camera over the D800E (which will surely cost less in the coming months). The Nikon D610 is pretty much just as good as the D800E and the D810, but will cost you significantly less. The entry level D3300 is more than sufficient for most people.