I believe this sort of questions have been asked more than once before, and you are going to hear different things from owners of each. I bought the 3805 after auditioning the Yamaha RX-V2400, Denon AVR3805, 2805, NADT763, Arcam AVR300, HKAVR630, and an Anthem Separate system. I brought my own CD's in all but the session with the NAD. The Energy C-9 was used for the Denon, Yamah, and the Arcam.
The Denon 2805 and 3805 did a very good job with the C-9 but the Yamaha 2400 did not do as well. When I auditioned the Arcam 300, I was able to AB the C-9, the Veritas V2.2 and V2.3i because the dealers have them. Switching to the 2.3i, I had to crank the Arcam up for about 6 increments in order to get the same sound volume. I believe 6 increments in the Arcam represents about 3 to 4 dB. Anyway, I like the sound of the 2.3i better, it seemed a little more transparent but the C-9 had stronger bass. At the end I went with the 2.3i and the Denon 3805 because the Arcam cost much more and I couldn't really say it sounded better.
I have since tried listening to my system with and without the help of my 200 WPC Adcom. I can hear some difference with the amp but I would not call it "huge" or "day and night". Obviously I have others listened to my system too and they could not tell much difference either. Others, and yours experience will differ, but I think it is quite likely that any of the models you listed will work reasonably well with the C-9. You can always add an amp down the road.
By the way, if you do a search here you will find a lot of responses to questions similar to yours.