[ctide]

Sennheiser makes fantastic products, even if they occasionally like to cripple them (http://mikebeauchamp.com/misc/sennheiser-hd-555-to-hd-595-mo...) and the sound quality is significantly higher than anything by Bose at a similar price point.

[wdewind]

I recently compared my Shure $150 SRHDJ head phones to my roomates $500 or so sennheiser hd 650s plugged into a $275 preamp and can honestly say the difference was hardly noticeable. I'm not an audio pro but I'm a musician with a good ear who has had a lot of kinds of headphones. For the money I can't justify sennheisers. Anything by Shure has been top quality, I've had a bunch of their stuff.

[Florin_Andrei]

Get the HD 6xx or the HD 800 if you can. I'm not saying the 500 series are not good, but the 600 and the 800 are way up there.