There aren't many headphones I've ever used that sound worse than stock-apple 'phones. (Except for maybe the ones you're offered on long flights).
Oh, I'm not using stock Apple phones. They're... ugh. I can actually not stand using them. Uncomfortable and sound terrible!
I'm using their in-ear set, which are *much* better. I just figure I might as well take this opportunity to go one better.
Thanks for the suggestions so far everyone!
On the Etymotics hf3's, would they be overkill? The iPhone itself will be driving them (no external amplification), and the music will be 256k AAC files (mainly rock, but some electronic and classical thrown in as well).