I owned the D2000 and HDP a while back; they made for an excellent combination. The warmness of the Denons is complimented by the sterility of the HDP. The D7000s are even a little warmer than their little brother, so I believe this pairing would be even better. The HD/P has plenty of juice for the low ohm Denons. I rarely had my volume pot passed 11 o'clock or so for moderate listening levels.
As far as the Fiio combo is concerned, the E7 is a great performer for its price range, but the DAC is a couple steps below the HD/P's. If you need a portable DAC/amp, I wouldn't rule it out, but if you're comfortable throwing down the $350 for the HD, I'd suggest just paying the bit extra and delaying the inevitable upgrade itch a little longer. Concerning the amp portions, the E9 is indeed a fantastic value, but it is still a notch below the HD/P's amp (although not nearly as big a difference as the two DAC portions).
