[David1961]

I once owned the SR-007mk1, and the amp I had driving it was the SRM-007t, and to me the 007 sounded veiled with not much guts driven by that amp, however I got to hear someone else's 007mk1 with my BHSE, and that amp turned them into completely different headphones. I also got to hear head-fier britneedadvice's HD-800 with his HDVD-800 and my GS-Xmk2 at my place, and for me the HD-800 has too much soundstage which in turn for me makes the music sound too distant.
So between the SR-007mk1 ( I've never heard the mk2 ) and HD-800, I'd always go for the 007mk1, that is driven by the BHSE .

 

[rawrster]

I have a pretty modest amp for my O2 and I just sold the hd800 a few days ago. Both have their merits butiI felt the O2 was the better headphone. Of course they also have different signatures so that has to be taken into account as well.

 

[minimus]

The conventional wisdom is that Stax SR-007 are better than any dynamic headphone. I personally don't really understand the appeal that well, finding them somewhat underwhelming every time I have heard them (probably because expectations were pretty high.). I actually prefer the Stax 507s to the 007.

My suggestion would be to buy a used pair of HD800s first, either here or on eBay. If you don't like them, you can probably sell them at little net loss and then move on to the 007. (The reason I wouldn't buy the 007 first is that the market for Stax is smaller because the cost of the headphones plus the ancillary investment in a Stax-compatible amp make the whole proposition too expensive and daunting for most hobbyists.)

The HD800s are my favorite headphone right now, but they need to be properly amped to sound good.

I would echo what others have said -- you should improve your source as a first order of business.