Clay
Get the AVR you want, the Denon AVR-X4000 is a good choice, at the best available price, but be aware of the warranty and the return policy of the vendor.
I agree with GIEGAR when he says "Try not to get too emotionally attached to an AVR purchase, they're almost a commodity item these days."
When you're first starting out, it's easy to get carried away with the myriad of different features available on AVRs. After you've used one for a while, you'll realize which features are important and which ones are not. Like many, you may find that the 80/20 rule applies – that 80% of the users only use 20% of the features.
You'll also find that AVR manufacturers introduce new models frequently. And, if you believe their advertising literature, the newly introduced features are so shatteringly good, that you absolutely must toss your old receiver and get one with all the new bells & whistles. Relax, it isn't quite so. What matters most in a receiver, after you set up your system, is the power amplifier section and the convenience of use. Many of an AVR's features help a lot during set up, but once that is done, you don't use them. Audyssey, for example, is definitely a work in progress. What is available a year or two from now will make today's version look outdated.
Thinking about setup made me look closely at the photos of your room. Other than the problem of the stairs, it doesn't look so bad to me. In fact, that vaulted ceiling may actually help with bass. The biggest detracting factor to good bass sound is cancellations and overemphasis at certain frequencies caused by opposite reflecting surfaces (walls, ceilings, and floor) that are parallel to each other. A vaulted ceiling is not parallel to the floor, and that may work in your favor. A large asymmetrical room may look like a problem to an owner who likes visual symmetry, but can be an advantage if you consider how sound waves propagate.
