I love using my iPod at the gym. I have a bunch of playlists for specific pieces of cardio equipment and I tinker with the lists to give me the perfect motivation for my workouts! It's so much better than the tapes and walkman I used to use, because you can change songs in an instant. I also got a really great protective case for my ipod at iFrogz. It has a clip, so I don't have to walk around with my ipod in my hand all the time.
I watch quite a few TV shows on this as well as music and generally works really work. I only wish the screen didn't scratch so easily and that the battery life lasted longer than 2 hours with video playing.
I have a Ipod Mini and now I have one of these too. Definately worth getting one. I got one of the refurbished ones (from apple.com) at 42% off the regular price. Bargain, as new, jus make sure you get a protective case asap!!