These cans are very interesting indeed.
If I were to compare them directly to the D2000s and 5000s and keep the summary under 100 words, I'd say that they are as clear and detailed as the D2000s highs, cool like the D2000s, with tighter bass than the D5000s (which were tighter than the D2000s). With much better mids than either. In fact, I didn't realize how recessed the D2000s mids were until I listened to the D7000s for a couple of hours, then switched to the D2000s. It's like the singers/rappers took a solid 5 paces back, away from the microphone. They are not as warm as the D5000s in any way...but I kinda like the D5000s warmth, to be perfectly honest. Yes, I can hear the difference between all 3 and their differences are clear. I can see why the D7000s are so popular: they do everything people want them to do.
I thought I would miss more boomy bass in the D2000s and D5000s....but once your ears adjust...they've adjusted. Going back to the D2k/5k's suddenly feel bloated. You notice the missing mids and say, "woah, wait. lemmie put these D7000s back on..."
If I have a complaint at this point, it's that because their highs and detailed nature is the same as the D2000, the highs can sometimes get too sharp for my ears. The rolled off highs were one reason I appreciated the D5000s so much, through the loss of detail was noticeable. So...here's hoping the highs will calm the hell down over time.
Needless to say, they've been in my possession less than 48 hours, so I look forward to seeing how the next month or so goes.
the HD650's...I can't tell yet. I don't have my good amp available to me until this time next week, so it'll be hard for me to tell what I really think about them until then. I think their clarity is amazing and their highs are detailed while still being rolled off a bit, so I appreciate that. they've never felt shrill or piercing. Alas, I'm a week away from fairly being able to critique them.
$0.02