Hey Sbc,
As a NAD T762 owner I can try and answer some questions for you. The feature sets should be fairly similar on the receivers you mention, along with the power ratings. I can't speak on the 3805, but I did have the opportunity to audition the 3803 veresus the T762 in my home. Although I enjoyed the sound of the Denon, I really preferred the NAD for the following reasons.
My front speakers are NHT2.5Is, 86db, 6 Ohms, and require a fair amount of power to produce and control the low frequencies. The Denon did a respectable job on the bass, but the NAD was able to produce a much more dynamic presentation of music and movies and I was able to literally feel the music at times. The Denon was unable to produce comparable quantity and quality of bass. I don't mean boomy bass, rather, realistic sounding bass.
The NAD is the only receiver I have heard that can make my NHTs come alive and sound like they are capable of. Granted, I didn't get a chance to hear Arcam and Rotel's offerings in my home. Quite simply, recordings sounded more natural and real when pumped through the NAD. I also have yet to stress the NAD even at rediculously high volume levels with all channels driven (I hope my theory that the neighbors car being gone equals nobody was home, hehe).
My best advice would be to get the receivers you are interested into your home and do a side by side comparison. In your home, with all your equipment, you will get the best feel for how each receiver will influence the ultimate sonic picture in your home. Your last question was about the cost. You should be able to find a NAD T763 for a little more than a 3805, and the T753 should be at or under the 3805.
One paradigm on these boards is that there is a ubiquitous sound amongst receivers and one should buy for a feature set you are looking for. I feel each receiver has the potential to sound quite different. I was initially settled on the 3803 and only brought home the T762 for kicks to compare them. In my home, to my ears, I felt the increased quality of the sonic presentation justified the few extra hundred dollars for the NAD. Good luck in your hunt for a receiver.
