Unless your D5000 is broken or ain't doing something you need it to do right now. Wouldn't hurt to wait until Oct. To see what comes out. Then decide. Although the D7k is an awesome camera and leaps above a D5k. I would wait. But i have a D7k and prior had a D80
>I have a D5000 > >The question of the day is, wait for the D7100 or D400, or buy >a D7000 now?
What is the D5000 not doing for you that you really want? Sooner or later a DXXX will come out that will offer even more MP's than the D7000. With perhaps an even tougher body. Maybe the High ISO will be even nicer... But are those aspects something you really need? Maybe yes...
But if you're not sure if you need a certain camera or lens, then you probably don't. That being the case, the money stays in your pocket until you are sure, and by then something even better will be out.