Distinguished speakers, all. With a fine list (and budget) like this, you should also take the time to listen to the Vandersteen 5A's. I think the 5A is a better speaker than at least two of the ones on your list, and you may agree....
I've heard all those speakers and several are absolutely world class.
Regardless of comments (including my own), speakers are a very personal choice that basically comes down to choosing the one with errors that disturb YOU the least.
While I agree with Sdcampbell about the Vandy 5A being an alternative, given the limits of your list, I would choose the Avalon Eidolon Diamond first place and maybe the Sonus Faber and Talon FIrebird tied for second.
That being said, I could choose my least favorite from the list and make it sound better than my first choice set up improperly and matched up with bad sounding associated equipment.
My point being that it's just as important when purchasing this quality level to carefully work to preserve what the speaker is capable of.
Basically you have to dig to find what it's best match is.
I'll add that the way each of those speakers interacts in your room will also have a significant affect on it's sound. One speaker you may like better in a different room than your own may not sound as good as in your own room. It could possibly sound better too.
I'd also do research and find more speakers in my price class. Maybe you can find some you can go and listen to. Two speakers at say 5k that are equally good will sound quite a bit different. With speakers it's very true that one man's poison...
I've heard the Avalon Eidolon and Eidolon Diamond, the Wilson Watt Puppy 7 (with Lamm 18w triodes) and the Talon Firebird. I really thought there was a significant difference b/t the Eidolon and the Eidolon Diamond, and the Diamond was my favorite of the bunch, followed by the Wilson/Lamm combo (many people feel the WP7's need something as powerful as the Krell, but they sounded quite nice with the Lamm.
Albert's words are born out of experience, and I know how much effort he has put in to finding good, synergistic matches. It's alot of work, but it pays off. You may have to experiment some, and you might even need to let go of equipment you are attached to to create the optimization you seek. The trick will be to hear the speakers at their best performance so that you are able to choose for yourself.
Of this group I never heard the Revel and The Talon.
Talking about the ones that I know, I prefer the Avalon Eidolon. Great speakers! But has someone said above, taste and set up are very important.
This is a big investement, try listening befere you buy. But if you ask me again what speakers I prefer from this group, my answer is the same - Avalon Eidolon.
if you like the character of your system now, i would say go for the nautilus 800's. depending on your tastes in music, i would say look at shahinian and vandersteen too.
Check out Usher's speakers, the bigger Dancer line, esp w/ the new Beryllium tweets. I have an older pair (w/ ceramic mids and tweets) and they're awesome, for much less money.
Given the quality of the speakers on your list and the quality of equipment, you should consider the Acapella La Campenalla's and the Acapella Violon's. These are excellent speakers.
I would add he Aerial 20 t to this list as well
You have to hear them in your room with your system, i think. I heard the Avalons at a hi fi show recently, with $50,000 cdplayer. The monoblocks used in this demo were $70,000 and devine to look at, but i forgot the name, so struck dumb was i by the price of it all and the lousy sound.This system in this room sounded awful with some cd's that i knew well. I am assuming that the room was totally at fault here.
I'll second the recommendation for the Aerial 20t. I've had big Infinity planars, (IRS-Beta), Wilsons (WP6), B&W (Matrix 800, 800 Signature), Maggies(3.5r) and many many more and I've lived with my 20t's for over a year and I still have no desire to move on......very rare for me!
Words of caution: The 20t's will ruthlessly reveal any poor links in the upstream chain, bad cables, etc. With quality frontend and system matching they will reward you.
Good luck in your quest!
You forgot to include on your list the DK Design Group's X-Dream.
I have owned the Avalon 's and now own the Firebird Diamonds. The Avalon's are a very good speaker for those that have a more analytical taste. I love the musicality and aliveness of the Talon Firebird Diamonds. They have the total package a tight very tuneful bottom end that in my humble opinion beats the Avalon. Also with the latest upgrade they equal the Avalons for midrange purity and both enjoy the diamond tweeter. So for a top to bottom comparison I would pick the Talons every time. Michael Farnsworth is also much more customer friendly then the folks at Avalon I have experienced them both. Also give Andy Payor a shot his Rockports are very competitive.