I've never owned any pricey headphones. So my budget considerations are in the 25 to just over 200 price range. From the fourteen headphones i have the one i would keep is-
Sennheiser HD 280 Pro- It has some of the best isolation i have seen comparable to ear plugs. In my some times noisey environment thats a real blessing to continue enjoying my music, games, movies without having to switch over to my bookshelf speakers. The sound has plenty of everything without overpowering each other. So i get my bass for single player games while having a balanced level of treble for the details especially for music.
For my second headphone it would be the-
Audio Technica ATH AD700- I game alot every day and listen to alot of music. I find the AD700 gives me a ton of detail other headphones dont for single player games like FALLOUT 3 and DIABLO 3. I can hear every sound in the game and with a completeness that fades out to the very last note and tone. They have a very speaker like quality due to being so open and i still find they have tons of slamming bass after i adjust the tone controls on my Onkyo TX-8555 stereo reciever. For my favorite genres of music like 1980s new wave (Gary Numan/John Foxx), ambient (Brian Eno/ Aphex Twin), Industrial ( Cobalt 60/Evils Toy etc), Classical ( everything ) , the AD700 completely satisfies with its level of precision detail without ever suffering from distortion.