I'm with Currawong here but also Mim overall. I settled on getting a barely used 100Mk2 because a have a lot of 'good' HiDef and still prefer it to others I could get for less than the high priced spread. It's close enough to the big boys and has a what I think a proper sig. Doesn't get quite as black or separated on 24/192 as the very best but not important as I only use it on the go. Other than a Hugo with good setup in front of it, I wouldn't use these for home playback anyway. Always thought the Ipod touch/Iphone were under rated on these boards but still prefer my AK at any def but not by a whole lot. Newer classics sound a bit washed out to me. I always test with wav since everything plays it and I don't have to deal with codecs unless that's what I want to evaluate. This on jh13s.
I also own Grado ps500 and some Stax besides a few cheaper IEMs but tend to only use the JH13s with DAPs. I can still hear differences on cheaper IEMs but find those differences become less important. Same for HiDef which can get cumbersome on the go anyway. I tend to use 24/48 or 24/96 wav on my DAP unless CD sourced(16/44) though I have some master dub tracks at 24/192 that are rather special and I keep on the internal memory. I'm not beyond using compressed material on limited space devices. I found AAC 400 CBR (nero encoder) surprisingly good. When I've used FLAC (redbook), I like the very slightly less etched character on my HiSound, I use the '0' setting. Still tags and reduces by 30% or so. I think some of the HiDef benefits are lost in FLAC vs wav even though it's bit correct.
All that said, I think the sweet spot for most consumers is a well chosen $50-$500 (c)iem and an Iphone/Ipod touch. Files, formats, usage, etc just doesn't warrant the high cost for differences many find to be unimportant or inaudible, especially with most of the manipulated source material available today.
My personal thoughts. I'm not debating them. What's right for me is just for me.