I have been using the Head Direct Reo for over a year with my various Sansa MP3's and classic iPod.  These in ear headphones replaced a pair of Etymotic Research 6i's.  Compared to the 6i's the Reo's are a much more neutral, cleaner sounding and comfortable headphone.  They're well constructed and can put up with a fair amount of abuse.
 
I haven't tried all the >$100 in ear headphones, but these are keepers.