Ted,
I have the KN6500 for over a year and was looking forward to upgrading to the kn7000, however after spending more than a few hours on one, I've decided not to.
The kn7000, is a great keyboard, and they've added a lot of technical stuff, like the SD-card, but the sound quality is the same as the 6500(the kn7000 speakers are a little more powerful). They haven't, in my opinion upgraded any of the samples or styles. They've just changed some of them.
So if you didn't own the 6500, I would say, you might as well by the 7000, but if you already own one, you might want to wait for the 7500.

Steve