I recently went to a music store and tried the Beats Studio headphones, and while I didn't really like the excessive "booming", I was shocked at just how incredibly comfortable they were. So I set out to find some cheaper alternatives, and stumbled upon myriad posts suggesting various alternatives to the hyped headphones I had tried out. After many hours of reading reviews and forum posts, I've decided that the Audio Technica ATH-M40x may just be the headphones for me, but I'm still a bit unsure, so I was hoping that maybe some of you could help me shed some light on some of the things I don't quite understand fully yet.
First of all, I plan on using the headphones as "general purpose PC headphones", but mostly for listening to music (primarily rock, no hip hop, rap, techno, etc.). I don't do a lot of gaming, but when I do, it's usually with friends on Skype (I have a separate microphone that I can use). I assume that the flat tuning and supposedly neutral sound of the M40x would make them perfectly fine for voice communication, but of course, I'm not at all sure. The second use case would be for long commutes (mostly by train or plane), but I have no real interest in spending the extra money on active noise cancellation (I also read that it's a bit of a hit-and-miss thing).
In wanting to use the headphones for my PC while still retaining the option of switching to my speakers, e.g. for watching movies with other people, I would like a setup that doesn't require a lot of plugging in and out (I'm also freakishly paranoid about wear and tear on audio ports). Ideally, I'd like to just plug the headphones into a USB port, and the simplest solution seems to be one of those tiny USB adapters for < $10, but would they just completely destroy the purpose of good headphones? From what I've gathered, the chip that converts from digital to analog is quite important here, but will the cheap adapters be any worse than the chip on my PC's motherboard (ASUS P5Q-E)? Would I need a dedicated DAC to get any decent results from the headphones? And if so, is it impossible to get decent results with something like a smartphone that only has the 3.5mm jack?
Finally, I've seen mentions of amps here and there - is this a necessary piece of equipment for headphones like the M40x, or only for a very specific type of headphone or non-PC, non-smartphone audio source?