MP3 players come in all shapes and sizes, but they share one common trait — good as they are right out of the box, a little accessorizing just makes them better.

Your MP3 player's already a great portable jukebox — that's its main function. You might have a player that also lets you watch downloaded TV shows or movies. But what about using your player as a video source for your home theater or as a music source for your car stereo? All you need are the right accessories.

First things first: protect your MP3 player

Some backpacks have special pockets designed for MP3 players.

Portable listening is the core use of just about every MP3 player, regardless of its size. It's a good idea to protect your player with some kind of case as you go out and about. There are a variety of cases available — some made for specific models, others compatible with many different kinds of players. Most feature a clear panel to shield the player's screen, and some include padding or a folding flap for even more protection.

If you like to listen on walks or workouts, you can find a case outfitted for easy mobility with an attached arm band, belt clip, neck strap, or wrist strap. Some cases even have built-in speakers for places where you don't have to keep your music to yourself. And you don't have to sacrifice style for functionality. Cases come in a variety of colors and designs, from conservative black leather to neon pink, blue, and green.

Want a "case" that can hold your books, keys, and cell phone in addition to your MP3 player? Check out the backpacks. They come in different colors, have a special pouch for holding your player, and storage aplenty for your books, laptop, and just about anything else you need to take with you.

Listening options on-the-go and at home

Possibilities abound for listening to your MP3 player on the go. One of the first accessories many people pick up is a nice set of headphones. The quality of headphones ranges widely, from affordable "sport" designs to noise-canceling models with impressive bass and clarity. You may also want to consider a Y-adapter, which lets you plug two sets of headphones into one player. This can be helpful for listening on an airplane, train, bus, or any other setting where you want to share your music with one other person.

At home, you can choose from a wide array of speaker possibilities. There are mono, stereo, and even 2.1-channel speaker systems designed for getting fuller sound from an MP3 player. And don't rule out your current audio/video system. A minijack-to-full-size RCA cable lets you run a line from your player's headphone jack to your receiver's auxiliary input, letting you play your stored music through your system's speakers.