The point may have already been covered somewhere in the preceding six pages -- apologies if I missed it -- but I had an experience this past weekend that again convinced me there's rare occasion to use iPod/MP3 players out on the trail: I was with a group of four on the NF Big Pine Trail, heading up to Sam Mack Meadow for a dayhike. The trip up went fine, but on the way down, the only person who hadn't ever done the trail round-trip was also the one wearing the iPod, and playing it at a volume which prevented hearing much else but music. Said hiker was in the lead, and managed to make a wrong turn at a fork, with about a two-minute lead on me. Couldn't hear us yelling, really yelling, to turn around. At this point I was on about mile 22 for the weekend, and my uphill running pace wasn't anything to be proud of, but up I went. Caught up when the iPod user stopped to strip off a layer of clothing, as the uphill route was inducing a sweat. That should have been the first clue, I suppose, since we were heading up the whole way in, hence the trip back should have been downhill.
Another vote for very limited iPod/MP3 player usage while actively hiking. Camp's another story. I can see some entertainment value there.
CT