Denon 6500 - Am I crazy?

Markedly different. In fact, in many respects a different hobby. The screen in my room gets used about once every 2-3 months. 

I use a 6300 from a few years ago in my living room 7.1 system. The 6000 and above series have better quality amps than their lower line. I could easily tell the difference from the 4100 I upgraded from. 
Will it sound as good as a 2 channel integrated or pre/power?  No. But it will still be quite good, and you get the benefit of room correction, which still isn’t common in 2 channel. 
I say try it and see if it meets your expectations. If it doesn’t, you can always add a 2 channel integrated amp that has a “home theater passthrough”, and get the best of both worlds. 
Or you could later just add an amp for the front 2 channels and use the denon as the preamp function, Including it’s room correction. 
I will also say, I personally find the B&W 7 series to be too treble forward. They might benefit from a tube amp or integrated for music. Or perhaps you like that type of sound?

Seperate. Or you'll end up with the worst of each. I'm with Elliot. 5.1 is plenty for two ears per head.

Hello,
You have to decide what is more important to you. I went through this same thing In the end I ended up with a Denon 4806 7.1 for theater and a emotiva preamp and Marsh sound Design ht500 amp 2 channel system with an imput pass through for home theater. I get my 2 channel system but I can use the two channel system to power the front. The amp I use has three channels with three separate transformers for powering the front three speakers. Everyone here is correct you only need a 5.1 system as long as you only have 1 row of seats. Because I have stadium seating I opted for the 7.1 to better cover the room. Subwoofers are very important for movies but do 1 ported connected only to your surround receiver . For music side do two sealed subs. You should get the matching center channel for your speakers. That being said you would be amazed how good tv and movies are in two channel. Later you can go nuts with adding more speakers. I believe only the front three need to match since AVPs have so much room correction now. 

re: Center Channel

Not trying to be ’right’, just to explain and pass on my experiences.

I have found, most of the center ’sound’ is still the phantom center created by equal sound from front l and front r mains. Another reason to get full range mains.

Center wants to be best at dialog, and capable of an output level to match the db level of the front mains. And easily and inconspicuously located.

Center’s location is critical to cement the bulk of the dialog on the screen, the engineers using front mains for off center front dialog. Timbre matching is now important.

Sooo, while it may seem, and is generally proposed to match the center OEM, often they are too big to be easily and inconspicuously located.

I’m no fan of Bose’s ’Stereo Everywhere’ i.e. their 901’s, and no fan of their ’full sound’ from small sources, clever for a kitchen radio, but ...

However, I was and am still happily surprised by the little Bose Center I recommended, I have been over many years, re-configuring my equipment and furniture arrangements, never tempted to replace it, THUS, I could not tell you a thing about any other center speaker.

I guess I am lucky it’s timbre is compatible with my mains.

It's real easy to try and be surprised by it, or return it.