Are some of you discounting Nikon? With the lineup of the D3 > D3S and D3X, D700, and D300 > D300S Nikon made much headway in the competitive market. But as often demonstrated in the past, it has been hard for Nikon or Canon to stay the lead.
These cameras are some of the best, even today! Many thought these cameras were becoming a little long in the tooth and impatiently waited for Nikon's updates. When the D7000 was released it received a lot of publicity with many waiting months for the camera. With this camera Nikon set a new path.
When the D4 was released there were many that were upset as it did not meet their needs. Yet D4 sales soared. The D800/D800E was released and it seemed many were up in arms about what is Nikon doing. Six- seven months later production is finally keeping up with sales for the most part. This week the D600 is released with many jumping on the purchasing wagon and a few complaints. Initially it looks as if the D600 well be another winner! All of these were not what most thought they needed nor direct upgrades. However you look at upgrades or replacements, sales seem to have excelled.
It will be interesting to see what Nikon comes up with for the next high end DX! And I'm guessing it will be as unanticipated and an unexpected non upgrade as was the D4/D800/D800E/D600. Nikon's got a $1,000 hole in the their line-up. They can't afford to leave it wide open for Canon.