Well, it depends on what IEM you buy simon. Some of them go half way to your brain, and have a very obtrusive fit. Others, can just barely sit in your ear canal, and feel perfectly comfortable. So comfortable, you can't even feel them. Now, the matter is, if you like sticking stuff in your ear, period. Which is fine if you don't, as many don't like IEM's. I'm not trying to convince you or anything, but it's always nice to have a pair of them as well. Because if I could only have two headphones, I would have a full-size, and a pair of IEMs.
Grado's would be a good choice. Just a word of advice, order from Amazon or an Amazon certified seller. That way, if you are certain you don't like them, you can send them back and get a refund to try another phone. This is exactly what I did with my K701. So I won't be ordering from seller's on Amazon when shopping for headphones.
Well, I think it may be final I'm getting the HFI-2400. And there are quite a few reasons I'm doing so. Like I listed above, there aren't to many headphones that like to be used without an amp. And out of the list I posted, the Ultrasone looked the most appealing. Besides, I've been keeping an eye on that headphone for a very long time. I like the "3D" sound from headphones. I also want to try out the whole S-Logic thing, whether it works or not. Detachable cable is a nice plus too.
But I also think Cnet helped me a bit. Yes, Cnet. Here is a quote from them about the 2200:
"To finish up, we plugged the HFI-2200 into our iPod. We were instantly wowed--the sound was big and weighty with exceptional clarity. The iPod had enough power to play the HFI-2200 fairly loud, but nowhere as loud as our reference Ultimate Ears UE-10 in-ear headphones. The HFI-2200's sound was much better than the far more expensive UE-10s, but the HFI-2200s' size will deter customers looking for a portable and practical set of headphones. Still, it's nice to know it can work with an iPod if the need ever arises. The HFI-2200 was a much better match with the iPod than Ultimate Ears UE-10, which we wouldn't ever recommend using with an iPod."