My favorite exercise is walking. I was an early adopter of the cassette Walkman, and my other players include a couple Mini-Disc players and several MP3 players of varying vintages (the oldest one came with a 32 MB
Here in suburban NJ we have Timber Rattlesnakes, but I've never heard one rattle. Also plenty of Copperheads, coyotes, black bears ... not to mention family dogs out for the night and distracted drivers. And a few days ago a jogger in Philadelphia was killed when a tree fell on her.
So, going out for a walk does
have some potential drawbacks!
Still, it's my usual exercise. And my German Shepherd doesn't think I do it often enough!
As I mentioned in the headphone thread, Koss PortaPro and SportaPro headphones sound great but let in enough outside sound that I've been able to hear dogs, cars and pugnacious suburban deer without a problem. I don't know if I'd be able to hear Timber Rattlers, though.
I have some very good isolating earplug-style headphones for when I'm at the car repair shop, etc.
EDIT: Got my snakes wrong!