I recently picked up a pair of Audio-Technica ATH-CK7 Titanium In-Ear Headphones from American Musical Supply.
The sound quality has really exceeded my expectations for in-ear headphones. There's a massive difference between the stock headset that ships with the N900 and the CK7s.
With a proper seal the bass response is excellent and well-rounded. Mid-range is very good although I find the upper range of the mids a little sharp, but the highs are nice and clear. Isolation is pretty good too. So far I find them fairly comfortable as well with no apparent fatigue or discomfort after prolonged usage.
The titanium casings are a little on the heavy side. The cable seems a bit short at 4ft but still okay. The wiring itself is flimsy and feels a bit delicate or prone to damage. The cable is somewhat rubbery as well which causes drag between layers of clothing. No major microscopic problems with the cable though...
Overall I'm quite happy with the CK7s and recommend them for anyone looking for a loud/full set of in-ear headphones.
I have a pair of Ultimate Ears Triple Fi 10vi (the one with microphone) and was very disappointed with the buzzing right out of the box. Fortunately, they came with an airplane adapter which converts to a plain stereo pin making them work as regular earphones. I would love to be able to use the microphone on these.
Also have Super.fi 5pros and Triple.fi 10vis. Both give great sound from N900 (or any quality source) but unfortunately as mentioned, cannot use mic cord because of the the buzzing. Pinout on the 10vi looks the same as the stock nokia, but i am wondering if there is different wiring or built in filter preventing buzz on stock nokia phones.
The bose headset ones work well, but you have to rewire them to make the microphone work. There is a small circuit board for GSM noise filtering 4" along the wire from the plug. You swap the two wires that connect to the third and fourth part of the plug.
