B&W Nautilus 803 or B&W 702 S2?

I'll put a couple suggestions that have already been recommended a lot.  The Hegel H160 will be a better and more refined integrated than the Rotel for about $1600-1900 used.  The H300 will be better than that, as the B&W speakers really need a high current / high power amp.  Other options could be the older generation Emotiva amps with a fuse upgrade (such as XPA-1 gen 1, or any of the XPR series).   Parasound A21 would also be a nice amp, and also works great with fuse upgrades.

Hmmm, seeing as how the Wilson Audio Alexx comes in at $109,000 retail, I don’t think that’s a fair comparison either.
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So, when comparing the cost of a B&W 803 D3 at $17,000 a pair. What speakers would be better AND cheaper?!?
Or even the 804 D3 coming in at $9,000.
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Ultimately, I don’t think I can come close to the performance of the B&W speakers at that cost, especially with the diamond tweeter. Now, beauty is always in the eye of the beholder, and there are definitely other speakers that are engaging, but they all have different characteristics. I have seen the brand Joseph Audio mentioned as a very competative speaker. They use the Seas Magnesium woofers and the Seas softdome tweeters. The Magnesium woofers have extremely high resolution and really "sing". They are definitely very engaging, but they do have a resonance peak at 5khz that can affect things and could contribute towards a slightly "metal" sound. The softdome tweeters are excellent and also "sing", but they do put a slightly tube like signature on the highs that are not their with the B&W D3. B&W D3 are slightly more laid back in the midrange, but have significantly more clarity in the highs.

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In the end, it all depends on what you want and what your preferences are.

@caphill - what is it about the B&W D3 that you don't like for music?

Huh, that's interesting.  I am a B&W owner and had the D2 and now own all D3s.  I have the complete opposite experience from you, caphill.  My B&W D3 are extremely engaging for music and are very rich and full sounding.  It at all, I would say the midrange is slightly laid back when compared to other more forward speakers, such as Monitor Audio and such.  I think it may be a synergy with your amplifiers / cables.

@caphill - just following up.  I did get a chance at RMAF (first time) to hear a bunch of speakers.  The Sonus Faber are definitely an excellent sounding speaker (my friend has a set of bookshelves mated with all Krell Evolution generation electronics that are excellent as well).
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On the B&W D3 note, I heard the 800 D3 in three different rooms.  The main B&W room had Simaudio Moon (if I remember right) and the sound was very clean and clear but did still have a little of that Class A smoothed over sound in the mids.  The second room was even more smoothed over.  In the third room, the 800 D3 sounded so bad that if that was my only exposure to B&W, I would totally walk out of that room and forget about B&W forever.  In actuality, I have to wonder how many speakers I heard that I would have thought sounded amazing, but were compromised somehow by an overly colored tube or too-smooth Class A amp, lol.  In reality, I love my B&W D3 at home here and was surprised that my system actually beats the crap out of a LOT of the RMAF rooms.  There were probably less than 10 rooms that actually sounded great to me.  Many sounded "nice", but just didn't reach that amazing level.
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I did hear Wilson bookshelf speakers and I will admit they were pretty damn great sounding. It was tube gear, so it's difficult to know how they will respond on Class AB solid state. 
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@topedwards - hopefully you listened to a lot at RMAF.  I would caution wit the Focal speakers.  I think they would be just fine with your McIntosh, but the Focal are fast and definitely have a thin/hollow midrange and midbass.  They would likely do very well with a Pass Labs full Class A, but your Mac will have a very laid back midrange and could be a great synergy.  I think you probably want a very high resolution to mate with your McIntosh.  Focal would be great.  Others that I have heard could be B&W D3 or Audio Physic.  The Sonus Faber definitely sounded good with McIntosh, but they are not the most detailed/forward speaker.

Oh, one more recommendation (and I did this in another thread) are the new Revel Performa Be speakers.