Hey ScottishRump (Pip),
Well, if you were looking for K701 and HD650 morsels, there are plenty in this thread! The first post will be most helpful — it's the guide. Each headphone review has a click to expand section for Mad's full review. If you want more, there has been more morsels of discussion on both if you go backwards from now rather than start at the oldest posts (excluding the guide post, which is very frequently updated).
The short version is, if you want an all-a'rounder headphone that is circumaural with great comfort, the AKG 701 65th Anniversary (fondly called the Annies) get a solid recommendation. It is more expensive than the K702 you mentioned, but this limited edition model has a flat headband offering more comfort for some, and a pleasing balanced tone that is a bare nudge warmer than the typical K702 (but not the aggressive "warmth" you experienced as part of the Grado house sound). Personally, I chose an AKG Q701 at half the cost, Chicolom posted a link to his more in-depth comparison one or two pages back, but the short version is the Q701 is closer to the Annies than another headphone brand, and still sounds great enough to have some great toe-curling audio-nirvana moments.
The HD650 also gets good marks, but it just presents things differently, more laid-back and FWIR stands out for "smooth mids." Also costs more. The HD598 and HD558 are cheaper, but the presentation is different... I suggest you read the first-page guide for impressions on those. The Sennheiser PC360 is basically an HD558 with a built-in mic – up to you if the price difference is worth it over buying a $3 clip-on lapel mic (dunno the price in Euro, but should also be cheap), and I haven't read any impressions on Sennheiser's new gaming headphone lineup but the PC360 comparison ought to orient you to the level of quality you can expect. Another "balanced" signature headphone worth looking into is the BeyerDynamic DT880: very even and "transparent" headphone, maybe less soundstage "width" than the AKG flagships but they are remarked for their comfort and near-monitoring accuracy.
The purchase list you laid out is a very good looking one IMO. I haven't read enough about (or auditioned) the Superlux headphones that look like AKG clones to know what they sound like, but for their asking price I expect you'd be giving up some refinement compared to the real AKG flagships... but those ought to still easily please you compared to the Tritton Ax Pros. Honestly, almost any of the headphones in Mad's guide are better than the Tritton's, read Mad's impression in the guide on those AX Pros. The other thing about your list... You
can drive the AKGs loud enough from the Mixamp alone, with the chat dial turned all the way to "game." The K702 (or Q701, or Annies) ought to sound pretty nice without an extra amp, HOWEVER (and this happened to me) over time you'll come to feel like something is being held back, and when you add an amp with lots of current supply and low distortion, the headphones will really show their potential by making each note/sound more distinct and adding more "air" and depth to the soundstage.
Personally, I bought Creative's Recon3D USB sound processor instead of the Mixamp, for half the cost, and I like that it works pretty well with both PC and console (Xbox here, but I may soon get a roommate with a PS3), without hearing the Mixamp personally I theorize the Recon3D USB has lower distortion, background noise, but also lower current, but it worked really nice for me once I added a tube hybrid amp made by Head-Fi'er Zigis. The Mixamp uses Dolby Headphone to process virtual surround (so does Tritton's AX 720 and Turtle Beach's DSS), but the Recon3D USB uses THX TruStudio Pro; THX works well for me, but I suspect it affects ears differently, I have more "morsels" talking about this in the thread linked in my signature. Head-Fi'er Nameless is selling his Recon3D USB for $70 USD, if you don't mind arranging shipping with him. I mentioned Turtle Beach's DSS earlier, that's probably the cheapest (2nd hand) recommended surround processing option for consoles, though we have a guy who likes his DSS2 as well. Last thing on surround processing/amping front, sometimes it's more versatile and forward thinking to find a home theater receiver with a headphone surround mode, for example Mad found a used Marantz receiver with Dolby Headphone that has a superior amp to the Mixamp, more processing options, speaker and input options, all in one convenient package (though large physically). Mad probably could've been "done" with just his Annies and the receiver, but he had to buy his Audio-GD Compass2 Amp/DAC and he is compelled to expand his guide every month... he probably wouldn't have tried the Annies and receiver if he wasn't that way to begin with, Love Ya Mad!
Hope you found this post helpful, and don't mind it being a bit longer than your own post (Mine's longer than yours is, Nyah
). From personal experience I recommend the AKG flagships and a surround processor, and if you want to spread out your cost you could survive waiting a bit to buy a dedicated amp, but eventually you'll want said amp
