and thought I'd share some thoughts since sitting in front of me just now i have (purchased over the last few years)
Sennheiser CX300 (£20)
Denon C351 (£35)
JVC FX66 (£20)
and just bought Apple 'in-ear' earphones (new dual driver ones) (£55)
I thought i was happy with the Denons but I liked the apple in-ear ones for the mic (for skype on ipod touch). Initial thoughts on the apples were.. oh god, what a waste of money. But it seems I've grown accustomed to the muffled sounds of the denons. So after some time listening here's some thoughts
JVC FX66 - i bought these for a long haul flight thinking they'd offer good isolation. Turns out because of the design they don't create a very good seal at all, but still ok to hear the bass as it should be. Sound is truly incredibly awful. Nothing good to say about these at all, not worth even £1. Having only used them really during 1 flight the like grill things are made of some very light fabric and coming apart already!
Sennheiser CX300.. i used daily for a long time, a couple of years at least, and liked them. Comparing them now, mids are muffled, highs are almost non-existant and bass is too much, far too much, that you can't hear any detail in the bass.
Denon C351, like the Sennheiser but clearer mids, and a much more controlled bass. Enjoyed them a lot and have recommended them here before.
but now having used the apple in-ear earphones... wow... crystal clear highs (maybe slight too much), detailed mid, perfectly controlled bass. The design of the tips that go into your ears create a far better seal too. Seal is like that of Shure SE210 (also owned) but easier to get a perfect seal and stay in place better. I'm really surpised and glad I gave them a chance because at first i didn't like the sound of them at all. Built in remote control and mic is a bonus.
Have also had the Shure SE210 (too hard to get a really good seal, cable was far too brittle, always fall apart eventually and boring flat (not a good flat) sound). Etymotic (or however you spell it) ER6i i've also tried. Shrill grating highs and no bass, unlistenable.
I've spent far too much on earphones I realise.
The apple earphones do get mixed reviews online, so I'd be interested to see if anyone else was as pleasantly surprised as me?
Oh and I was testing with ipod touch...