[Maxvla]

You might like a system like mine:

Matrix X-Sabre ($1100) -> Headamp GS-X mk2 ($2800) -> balanced cable of your choosing ($200-300) -> Senn HD800 ($1500)

Puts you at just under $6k. I love the sound (I did audition it), but the wait for the GS-X is getting to me (1 year in 2 weeks).

If you want something you can put together soonish I'd look at either a DNA 2A3 Stratus ($2700) or EC Super 7 ($1800)/Zana Duex ($2200, SE only) or Cavalli Liquid Glass ($2900, tube rollers dream amp) or perhaps a Cavalli Liquid Gold ($4000) or Eddie Current 2A3 mkIV ($3900), but the last two push the budget right near $7500.

 

[TwoEars]

+1
 
A HD800 system like that is a very good substitute for stax rig.
 
There is also the bryston headpone amplifier which is readily available.

 

[rgs9200m]

my 2 cents:
LCD3 + a good tube amp, the best you can afford (I like a Pinnacle or RSA B52), but I'll let others recommend a good more affordable amp
(I would read the reviews of the Apex Teton, which I have not heard but I'm thinking is Pinnacle-like 
as the review comments sound exactly like what I hear in the Pinnacle).
 
But IMHO, go for tubes whatever you do to get that inner life.
 
I also find myself actually liking the headphone experience above speakers strangely, especially with the modern crop of phones.
A TH900 would also be on my short list, also with a tube amp. (Get both LCD3s and TH900s if you can swing it, as 2 phones for variety and judging upstream gear I think is a minimum number.)
 
Last, maybe later on when you get some experience with your system, get some very good interconnects and power cords, no matter what anyone says about placebo affects.
(And also get a good power conditioner later on.)
 
I chose those headphones because 009s and, to a lesser extent, HD800s, are harder to get right and could send you down a wormhole of equipment trading.
 
I also really love Grado GS1000i phones (which don't get a lot of respect around here outside the Grado threads), but they are extremely light, comfortable
and sweet sounding with tubes, With a bass which, while not traditionally super tight and detailed, that is somehow wonderfully satisfying to me,
which also describes the entire GS1000i sound, and I can for some reason use these phones for much longer sessions than any other phone without any fatigue;
they are just plain musical and balanced for me. They have just the right combination of openness and intimacy, with especially tangible images.
(They are the pick of the Grado litter, as I didn't like the PS1Ks much, which were heavy and too hard-hitting sonically.)

 

[David1961]

The most detailed and transparent headphone I've heard is the SR-009, and since using Psvane EL34PH tubes with my BHSE, my 009 / BHSE is the best headphone combo I've ever heard.
I think my LCD-XC / GS-Xmk2 also sounds very good, but IMO not to the same SQ level as my 009 / BHSE.
Yes the 009 / BHSE combo isn't cheap, but in this case you get what you pay for.

P.S. IMO, to get the best out of the 009's while driven by the BHSE, using the PH tubes is a must.

 

[project86]

Nothing wrong with piecing it together bit by bit. I'm assuming you still enjoy your amp and preamp, so you could always add in a Woo Audio WEE transformer box. That would be cheap and allow for pretty decent sound - you could grab an 007 or even an 009 and still be within budget. Would it be ideal? Of course not.... but still damn enjoyable.
 
Personally I'd grab the WEE, an 007, and since you've kept the budget so low, upgrade the Benchmark as well. You could do their DAC-2 or go with any number of other good options. The result would still be under your target price.
 
Later, you could look into adding a proper stat amp. Maybe an Electra, or a DIY KGSS or KGSShv, maybe even go all out with a BHSE. Stat amps are a whole different world to explore and you don't want to rush into it without preparation.

 

[bahamaman]

project86 - sorry that I haven't updated my sig. I'm starting with nothing, save for some Denon D7000s, which will be sold once I know where I'm going with this.

I sincerely appreciate all the excellent advice. I think I'm leaning toward moving back into a Stax if I can make the budget numbers work.

 

[project86]

I see. Having not heard any of the more recent major players, it might be worth while to get yourself some first hand experience. A local dealer with units for demo is ideal but rare.... local meets can be great if you happen to have one pop up in your region. And lastly, The Cable Co has a "Lending Library" program where one can basically rent the headphones for a reasonable fee. The rental fee even applies to the price if you end up buying.
 
This would mostly be for exploring the dynamic and planar models out there - if you are sure about Stax, then I'd stick with those.
 
You already know you like the 007 so that's a good way to go. If it were me I'd probably do:
 
SR-007mkII ($2500 or so)
SRM-323S ($999, better than the other current Stax brand amps imho)
BMC PureDAC ($1800) or Anedio D2 ($1300) or Benchmark DAC-2 (under $2k) etc
 
For good measure, I'd also add in another non Stax headphone for good variety. Using the built-in headphone amp in any of the above units would sound nice with an LCD-2, or Alpha Dogs, or some custom In-Ear Monitors, etc. I love my 007 but variety is fun to have at times. 

 

[Currawong]

I'd honestly go to a meet and audition a pair of LCD-3s and a pair of HD-800s. Neither will have quite the presentation or even the effortless treble of the Stax, but if you don't compare directly, you can get pretty close. The problem with getting a TOTL Stax rig nowadays is: You can't without waiting, sometimes up to 2 years for the amp, if you want t a Blue Hawaii SE.

 

[Happy Camper]

The HE-6 are the 7s with impact. You can use your speaker amp to play them saving the cost of an amp.

 

[TwoEars]

  ...sometimes up to 2 years for the amp, if you want t a Blue Hawaii SE.

 
That's crazy, headphones really are booming aren't they?
 
That being said I've seen the Blue Hawaii in the for sale section here a couple of times. They tend to go pretty fast but you can get lucky if know what you want and you're ready to pounce on it.

 

[Surfski]

I'm not sure I can offer a comprehensive strategy but here is a different take on the suggestions so far:
 
Source. Definitely consider a good DAC. If you are looking for inner detail, the subtleties a good DAC can reveal really add up. This is even a bigger deal with the advent of high resolution computer based playback. This will impact your budget priorities. The Ayre QB-9 is the first DAC that I thought REALLY brings the music and detail together. There are definitely others. 
 
Keep it real. Your priorities may have changed. I recently moved away from focusing on a summit system and went for a Chord Hugo. Glad I did. It got me off the dime plus the combination of quality and mobility is really fun. It also scales quite well. 
 
Of course, I'm still lusting after summit rigs but I am now slightly more realistic about how it all needs to work together and my patience for system iterations. But wait! That's part of the fun! What was I thinking...

 

[Maxvla]

The Hugo is certainly a nice piece of gear, but it's a big compromise. As good as the sound is, it can't touch a desktop rig that is equal to its price, and it's a little large to be portable, especially with things plugged into it and poking out the sides. Transportable, yes.

 

[Surfski]

Oh I pretty much agree with you. My point was to consider more options and practicalities...as well as the contribution a good DAC can make. I also agree that the HD800 is best served by a great balanced amp.

 

[David1961]

I'm lucky to have the headphones and audio equipment I wanted, but if I was starting off again and only had so much money spare, I'd get the LCD-XC, a good portable amp, which in my case it's Pico Slim, and an iPod. ( the LCD-X's might also sound good with a portable set up, but I've never heard them so I don't know )
I sometimes use my LCD -XC's with my Pico Slim / iPod and I'm very happy with the SQ.
Then I'd save for the SR-009's and BHSE, making sure I had the money to get a quad of Psvane EL34PH tubes.

 

[NZtechfreak]

The HE-6 are the 7s with impact. You can use your speaker amp to play them saving the cost of an amp.

I'd go the 6 as well, apart from sounding awesome leaves the bespoke budget looking very healthy.