With headphones, I've only tried limited numbers, so my experience is definitely lacking. My knowledge is also very dated as I have not kept track of head-fi and related sites since last August.
Before I put a pause to my obsession, Anedio D2 / Nad M51 / Antelope Zodiac -> Cavalli LL / BHSE -> Stax SR-009 seemed like a good way to go (see
High-End Electrostatic Headphone Amplifiers for the Stax SR-009 - YouTube). I thought DAC can be upgraded later on, but I have to spend on Stax headphone and amplifier anyways.
HD800 and
EC Balancing Act was another option I considered. But, there are plenty of
other amplifier options across price range for HD800. Other headphones that I thought of include
Fostex TH-900. I had considered Beyer T1 seriously for a long time, but they seem inconsistent; so chances are that your T1 may sound different from mine. Audeze had build quality and weight issues and I thought their bamboo LCD-2 solved it somewhat, but have not followed it up. I also thought of Hifiman HE-6/HE-500 as alternatives to LCD-2. HE-6 is notoriously hard to drive, but HE-500 is much easier.
I think this was supposedly to be good as well:
New Flagship from Audio-Technica: ATH-W3000ANV, 50th Anniversary Headphones.
That's where I wanted to go until I looked at my 'free to spend' bank balance
. But, considering my interest is not what it used to be when it comes to spending on audio gear, I am sticking with my cheap combo of Leckerton UHA-6S MKI and HD600 / DT880 these days. Both headphones do better with DacMini CX -> Burson HA-160 as that combo gives them more power. Strangely, even though I think DacMini CX may be a better DAC than UHA-6S, I am more satisfied with UHA-6S than DacMini CX (little things that satisfy me + less glaring mistakes for my taste
vs more things I find lacking compared to my ideal one-dac-amp-I-can-live-with-forver, perhaps). I'd put HD600 and DT880 in the 'good, better than many others, but not great' category in terms of SQ. Though I've not heard better headphones, I am just basing it on my experience in IEMs.
HD600 is good across genres, but it's not as detailed and not as 'lively' as I'd want (more like 'edgy when needed'). HD650 would be it's close cousin, adding more weight to the lows and mids while pushing treble a little back in the mix. DT880/600 is relatively brighter with a metallic timbre up top which might put off some, but it is more suited for my preferences than HD600. As far as build quality and comfort goes, HD6XX is much better, as you can replace each and every part individually right down to the drivers - a good option considering that it can last years and years as long as it's not mishandled. I've heard that HD650 is slightly harder to drive and hence will keep on improving with better amplification. HD600 is said to be relatively easier to drive and hence may not show such a wide variance with amplification. This may be the range to look at if you are upgrading from HD598.
Grado SR225 from what I hear is a good option (which I considered buying along with HD600 and DT880). But Grados are a love or hate kind of signature and they leak sound, so they may not fit everyone. The old discontinued Denon phones which were made by Fostex D2000/D5000/D7000 with or without mods (have not read up on the newer offerings, which did not look as good) are another option to consider if one has a liking for bass.
There are various Fostex T50 Mods (which can set you back by $400-600) :
http://www.head-fi.org/a/fostex-t50rp-modification-summary-links-wiki, of which some I know liked LFF's mod (
Inner Fidelity's measurements). Of course, there's our own
Ortho thread.
I am sure that there are plenty more depending on your sound signature preferences and leniency with the budget. There are plenty of other options as well. You can look at
2012 Head-Fi Holiday Gift Guide (Over-Ear) - Head-Fi.org Community, but look past the sales pitch and read more on whatever you filter.
My 5 Zimbabwean dollars.
