[spykez]

I've been looking at the two non stop for weeks and can't really decide which one I want to go for. I have no problem paying the price of the 700 but they both sound like they're sooo good. I unfortunately live in Madison where the only brands that are sold is Bose and Beats and whatever iDevice is popular because college kids with parents money don't know any better.
 
What do I listen to?
 
Classic 80's metal (metal church, ozzy, savatage, helloween)
Power Metal (Myrath, Kamelot, Hammerfall, Threshold)
Enya, Righteous Brothers, Bohren & der Club of Gore
 
I mean I listen to everything, lately it's more jazz and classic rock/metal than anything.
 
I also game online with them pretty often (I play almost everything).
 
The most deciding factor is comfort, which compares closest to the HD 598, because those are the most comfortable headphones I've ever worn and wear them for hours without realizing it.
 
I really like my mids to be a bit more forward, I love crystal clear highs (highs don't bother me at all) and I don't need ear shattering bass so long as it's slightly punchy but present.
 
I know the mentallity that more $$ is better but it's all about the sound.
 
So sell me on both Pros and Cons if you will ^___^
 
I have a Schiit Modi -> Schiit Wyrd (it'll be here Friday) -> Little Dot MKIII (soon to upgrade to a Valhalla)

 

[Greggo]

You are clearly destined for the HD700, it is the better headphone for every area that you mentioned and you declared yourself mostly immune from the HD700's only flaw, and that is a treble spike/dip that can irritate some folks out there.
 
I own both, and highly recommend that you plan on doing the same unless you decide that the HD598 is good enough for a long term compliment to the HD700.  Here is my take on how each will stack up for you:
 
HD700:  A different feel altogether from 598/600 due to physical design, most find them to be more comfortable. For me, they are the most comfortable headphone I have ever had on my head. Better genre flexibility, better bass, better resolution/detail, better PRAT and drive so I think the HD700 is going to be a step up for gaming and for rock/metal and jazz.  For classical, it depends, the pluck and decay of strings are superb on HD700, but the balance and truth of timbre through upper mids and highs is better on HD600, so some would say the HD600 is superior for classical music.  For acoustic guitar, folk, blue grass, country... I would take the HD700 every time.  The HD700 will also scale better with capable electronics and have far superior imaging.  Based on your criteria, the HD700 is the clear winner IMHO.
 
HD600:  Probably about the same or maybe just a smidge less comfortable than HD598, these are very similar physical designs but the HD600 probably has a bit more clamping force so you need to break them in.  I have not owned the HD598 but I did have the HD555 for a while and listening to the HD598 in a hifi shop I found it to be a more forgiving and having a more consumer oriented balance (warm bass, more sparkly highs) than the HD600.  I bought the HD600 after having the HD700 for a few months because I wanted a "source of truth".  I planned on collecting a wide range of headphones and I wanted to have one or two in my collection that would stay as a reference for truth to source in terms of balance and general presentation.  I feel that the HD600 and Focal Spirit Pro both accomplish that for me. I have also come to appreciate the strengths of the HD600 and feel it is a clear step up from 555/598 if you intend to have a real amp in the mix at some point.  I often recommend the HD600 as the true "one and done" headphone for anyone who is a new audiophile or starting down that path as I think it is the best value in headphones at the moment along with the ATH-M50x.  I recommend the latter to folks that want clean punchy sound that works just about anywhere on anything, and the HD600 for those who want more of a high end audio experience.  The HD600 just keeps me honest, and helps me better appreciate the strengths and weaknesses of all my other headphones.  I will never part with it.
 
Hope this helps, best of luck with your headphone pursuits.

 

[Click]

Based on your description, HD700 is the obvious choice. Be warned though, HD700 will reveal flaws in your music files, making badly recorded/mastered/low bitrate files sound like crap. The opposite is true too. HD700 will make well recorded/mastered and high quality files sound amazing.
 
I mainly use my HD700 to listen to my FLAC collection, gaming, and watching movies / TV shows. Streaming music via Google Play Music or my .mp3 collection is better suited for my other headphones and IEMs.
 
You also need a good DAC and tube amp to bring out the potential of HD700. Looks like you have that covered with an upcoming Valhalla 2 purchase. HD700's treble spikes are tamed and smoothed out with a good tube amp.