Hey guys, I've been lurking these forums and other sites looking up reviews and information on all kinds of headphones. My birthday is coming up on september 19th, (turning 21!!), and I asked for a pair of headphones but I just can't decide which ones will suit me the best. Brands I've looked into are Sennheiser, AKG, and HiFiMAN. I listen to all types of music and I love some quality base. I'll be using the headphones just around the house and at the university library which makes me lean towards a noise cancelling headphone like the sennheiser PXC 450. My roomate just purchased the Bose Quiet Comfort headphones and they sound decent, but I didnt want to go the bose route. The only reason I wouldnt want a noise cancelling headphone is that I dont think the sound quality would be as good as the Sennheiser 598s,600s, or 650s. So how do noise cancelling headphones compare to open back headphones as such? Also, the Sennheiser RS 180s recently caught my eye due to them being wireless, but again, how would the sound quality compare to even the HD 598s? Sound quality is the main factor, but I dont want to spend more than $500. I would also sacrifice a little sound quality for a noise cancelling headphone is there isnt that much of a difference. The headphones I currently use are beats which I got about exactly 2 years ago during the whole beats "hype" . I've been using electric tape to hold them together and i've also realized I over payed for these headphones which is a little disappointing so I do not want to make the same mistake this time around! So overall, how would you rate the following on Sound Quality? (and compared to beats, because thats the only headphone I can compare quality to). Sennheiser: HD 598 HD 600 HD 650 RS 180 (and maybe the RS 220) PXC 450 AKG: 495 NC 550 HiFiMAN: 400 those are basically what i've been looking into. thanks for the help!!!! sorry if this is a stupid first thread, dont flame me!