There are other threads here that are relevant in part to this question, but everyone's dilemma is a little bit different. Here's mine:
My wife and I both shoot D90s. We are going to on a photography trip to Iceland in August (with Focus on Nature/Tony Sweet). Before then I want another DX body (FX is not an option now for a variety of reasons) so that my D90 can be a backup body for both of us. (I don't want to have our expensive once-in-a-lifetime trip spoiled by a camera failure.) The D7000 (or its successor) is my first choice for the sensor/feature upgrade over the D90 in a camera that retains the functional layout of the D90. I also want to get this new toy this spring, in plenty of time to learn it (and get any glitches repaired under warranty) before August.
With that background here are the choices I see:
1) Wait for and buy the D7100 (?) if it's announced and available between now and April. This would be a slam dunk if I had any confidence that the D7000 upgrade was in fact in the pipeline. However, I am beginning to doubt that Nikon will introduce a high-end DX body of any kind in early 2013 based on the complete lack of leaks and rumors so far. Also, if Nikon's next DX camera turns out to be the mythical D400 instead, then the likely added expense and the different layout and "feel" (compared to D90, which I like very much) will make that purchase a more difficult decision.
If it gets to be the end of March and no new DX body has appeared, here are the alternatives that I see:
2) Buy a new D7000 (~$900), get a full year warranty and plenty of time to adapt to it.
3) Buy a refurbished D7000 (currently $750 from Adorama) and get a 90-day warranty.
4) Find a used low-actuation D7000 being sold by a fellow Nikonian ($??) and forgo the warranty. (My wife's D90 was acquired this way and it has performed as if it were purchased new.)
5) Forget the upgrade and pick up a third inexpensive used D90 body to use as a backup (not really interested in this over #2, 3, or 4, but I include it because it is a formal option).
Then there's the whole issue of the continued availability of the D7000 this year, thanks to this post yesterday on Nikon Rumors: