Since you've done many weeks of research, I bet you know more than I do about these receivers.
If you want usable information, without posters fearing they will be wasting their time, you really ought to share what *you* have learned, and what particular things attract you to any certain receiver.
Personally, I'd go for the Denon for the feature set, namely the Audssey suite, but in fact I'd keep waiting for XT32.
IF* I didn't care about Audyssey suites, I'd probably go with Yamaha because I have the impression that they are very reliable, and they also have a reputation for clean preamp sections. The first thing that I would investigate with Yammy is the bass mgmt, and how flexible xover choices are.
I don't have the slightest clue about how the amp sections compare, perhaps because I would probably never use the amps.
For me, the feature set is the determining factor.