Which headphones should be purchased?

"I never tried the etymotics. I was a little concerned with having a speaker THAT close to my eardrum. "

I know what you mean, but the design blocks out all external noise...you should actually be listening at a lower volume level than you would with other headphones. The difference is that you're hearing all music and no background noise. I plan on picking up a pair whenever it's financially feasible.

I have a pair of Etymotics 4S and a Headroom Amp. Noise cancellation is second to none. Sound quality is a good as any headphone period, it's all personal prefernce. When you have great noise cancellation, you won't have to play your music at highter levels to cancel out the noise to enjoy your music. I would not worry about hurting your eardrums. The negative is that the 4S's need an exteral amp. However, Etyomotics makes a version that does not require an amp that is very close to the sound quality of the 4S called the 4P.

Suggest you check out the forums at headwize.com and headfi.org. Use their search engine and you should find some useful info. I would avoid the Bose headphones. For traveling I use cheapo noise cancelling headphones which stink sonically. In the fall and winter, I usually use Grado RS-2 headphones, which I personally prefer over the Sennheisers. The Sennheisers are good, but too difficult to drive compared to the Grados and Ultrasones. In the summer, when the a/c is on and I want some isolation I use the Ultrasone HFI600. This particular Ultrasone is a sealed back headphone and is the only sealed phone I have found that rivals an open back phone in spaciousness and soundstaging. I have tried various sealed headphones such as Sennheiser, Sony, Koss and Denon but have found nothing that rivals the Ultrasones, which are not widely distributed or well known. They are mostly sold in the US thru pro audio dealers or are available at meier-audio.com. Tonally, they are to headphones what the Spendors are to loudspeakers. Yes, they are even a little smoother sounding than the Grados. You may not like the way they look either. However, for plugging directly into a portable and for a sealed back phone, I have found nothing better. I think Ultrasone may have changed the design of the HFI600 since I got mine and the current model looks better and folds up, but may not be as comfortable. Good luck and enjoy.

Has anyone heard the Bose headphones and compared them to the Sennheisers or other audiophile Headphones?

I own several high-quality headphones, including a Sennheiser HD-600. A friend of mine let me hear his Bose noise-canceling phones. It was not a good test for sonic quality. We were using his music, his personal stereo and the test was quite brief, so based on that test I can say that I was not wowed by the fidelity or sonic quality, but the noise-canceling ability of the phones is quite remarkable. If I were making a choice for the application where you wish to use them, I would carefully audition the Etymotic's vs. the Bose. Ultimately, I think that the sonic quality of the Etymotic's will override the Bose which, at least in my poorly set-up listening test, did not come close to a high quality headphone.