Okay, I've decided that I like the Shure earphones that arrived on Monday. They're kind of slow to put on and take off, and it's hard to interact with people in my office with them in, but that's not necessarily a bad thing :-). On the other hand, once I switched from the rubbery earpieces for it to the foamy earpieces, it's a lot more comfortable and it sounds better. It's still not quite up to the sound quality of my Grado SR-60 headphones, but they're still pretty good, and the extra noise blocking means that they're a lot more comfortable to use. Plus, I used the Shures for ~6 hours yesterday (in <2 hour chunks), and I didn't feel beat up at the end of the day; the Grados might sound a bit better, but the earpieces are kind of uncomfortable and the utter lack of sound shielding on them means that I have to turn them up to get over the background noise in my office. The combination of loud and uncomfortable gets tiring after a while.

Strangely, the Shures seem to sound better with the iPod then the Echo Indigo. I need to do more testing (laptop/ipod, shure/grado), but all in all, I'm pretty happy with the iPod/Shure setup.