I'm a big fan of Shure buds....I have both the E2C and the E3C. The E2C has better bass, but is less sensitive and is a bit more troublesome for maintenance (tips are more expensive, and those wax screens are annoying!). The E3C has less bass response, but is far more sensitive and far more accurate. My only gripe on the E3C is the iPod white...but that's just aesthetics.
Overall, I consider the E3C the better value...the E2C, while being good, was just not the audio epiphany I was expecting compared to the Sony EX-71. For some reason, I think the $150 mark seems to be the magic number for both headphones and canalphones both.
As for MP3 players and the Shures being overkill...not at all. Just from a noise reduction point of view...the E3C with foam tips can damp out the jet noise from even the worst seat on the plane, and still not need significant volumes to hear your music.
Plus I found great results encoding my own music...192KBps 44.1khz MP3 isn't great, but it's not bad either...however it seems to be far better sounding than 128kbps....at least sounds like cymbals sound reasonable at the higher bitrate.