Newbie HiFi Headphone & Amp pairing suggestions

Hi Gang,

I know headphones and headphone amp pairings are very subjective and vary person to person. Being new to the HiFi world of headphones, I've narrowed down (I think) a new headphone purchase to:

• Audeze LCD-X
• HiFiman Arya
• Sennheiser HD800S

I've not had open ear headphones before but have a relatively quiet office in the house (when the kids aren't around) and am excited to explore the HiFi headphone world. 

So, I'm curious if any of you have had any experience with the above and would make any recos either way and if so, what amp you reco pairing with it. I have a buddy who has the Viiolectric V281 and swears by it but it seems impossible to find (and quite pricey).

Lastly, is there any hope of getting a great DAC and headphone amp in the same unit or would you reco separates for longevity's sake?

@fourminutesong -- Yes, Audeze are very heavy. If you plan to listen for more than an hour or so, I can tell you that you'd notice the weight. But IMO, you get used to it. 

My current setup is a Node 2i >> Audio Mirror Tubadour II DAC >> Quicksilver headphone amp (tube-based) >> Focal Clear or Sennheiser HD6XX.

If you can find a used pair of Audeze LCD Classic, I say go for it. Even if you don't like it, they are easy to sell in the used market.
A very good headphone amp for $400 or $500 is the Topping A90. I compared it directly to my $3K Benchmark HPA4 and it is pretty close. Neither of those 2 are warm. However a warm DAC like the Audio Mirror Tubadour may be nice with them and give the warmth the OP is looking for. Given me a few days to test that last part out.
Went with ordering the LCD-2Classic. Excited to get them.

What do you think of the Mytek Brooklyn Dac or Brooklyn Bridge? I need the headphone amp and a DAC so thought they may be good together. 
I use the RME ADI-2 DAC. Aside from its DAC, it can be used as a preamp. It has a headphone amplifier. A giant killer, it comes with a remote, various filters, switchable crossfeed, loudness, and EQ. 
@umn how does it sound to you? do you miss not being able to play MQA? that one is on my list too. not sure how the DAC compares to the Mytek....