I'm currently playing my flac files on a rockboxed 120gb ipod 5.5 through my absolutely great FS Atrio M5 iems. It sounds nice but I guess the mids could be a little itty bit more forward. I love the comfort, bass, isolation and general sound of my M5's but the battery life on the ipod and the proprietary cables are bugging me. And sometimes you just want to try something new :)
I've been looking at the Hifiman HM-601/602 but then I would need to cut down to 32gigs and battery life would be the same as I'm getting with the iPod. The HM-601 supposedly sounds absolutely fantastic, very musical and somwhat warm - The same has been said about the M5's so should I get a colder, more analytical source for them? Looking at Cowon, the 160gb X7 is available at £250, packing native flac support and 103 hours of music playback on a charge.
I listen to just about every kind of music, I can easily go from Rammstein to Rihanna to Ravel within half an hour which is why I love my Atrios - everything just sounds gooood. It also means that I need a lot of space for my music as I love bringing EVERYTHING with me :)