They're everywhere: white headphone cords trailing from a pocket or bag to the bobbing heads of music lovers enjoying their tunes on the go. Deciding you want to be in on the fun is the easy part; deciding exactly which player to buy can be a bit more challenging. Although the basics of the many iPod options are the same, the details make each player as individual as the person who owns it.

When looking for your ideal iPod, the key is knowing what you want. And figuring out exactly which features you would like in your player is the best way to start.

The touch raises the bar for what is possible in portable entertainment and information devices. Weighing a bit more than 4 ounces, the touch connects you to the World Wide Web no matter where in the world you roam. Surf the 'Net, send an e-mail, get directions, check the weather, watch YouTube videos, or follow your stocks--it's all possible, thanks to Wi-Fi functionality.

Also, the touch provides access to the App Store, Apple's ever-growing source of free and paid games and applications to install on your device. Keep track of Facebook, Twitter, or other social networking sites. Play games like Super Monkey Ball or Moto Chaser for a unique gaming experience built on touch technology. The world's best developers are cranking out more and more ways to enjoy your touch, helping to ensure that the best keeps getting better.

Want more? No problem. How much music you can load on the touch depends on which version you take home. The 8 GB model holds 1,750 songs; 10,000 photos; or 10 hours of video. The 16 GB model gives you up to 3,500 songs; 20,000 photos; or 20 hours of video. And with the 32 GB model, you can carry a whopping 7,000 songs; 25,000 photos; or 40 hours of video along with you.

Even navigation on this device is entertaining. As its name implies, the touch relies on physical contact to move through its many features. A unique interface allows you to "fly" through menus displayed on its generous 3.5-inch display while using a "pinch" motion to zoom in on what you want to see most. Add an accelerometer for motion sensing, real-time 3D graphics, and 3D positional sound, and you've got even more ways to play.

Start shopping for an iPod touch.

Weighing in at just over 4 ounces, and with a slender metal enclosure measuring 4.1 x 2.4 x 0.41 inches (H x W x D), the new classic is available in two striking colors: black and silver. The 2.5-inch color LCD lets you enjoy photo slideshows, movies, and TV shows from the iTunes store or your own collection, and iPod games like Vortex, iQuiz, or Klondike.

Does the thought of scrolling through every song you've ever downloaded make you cringe? No need to worry. In addition to traditional iPod navigation, the classic includes Cover Flow, which makes it possible to search for songs by album art. Use the Click Wheel to flip through album covers, then select one to automatically see its track list.

Another new addition to the classic is Apple's Genius feature. If you like a song and want to hear others like it, Genius finds the songs in your library that go great together and makes a Genius playlist for you. Count on Genius to create a mix you wouldn't have thought of yourself. Start shopping for an iPod classic.

The nano comes in two different capacities. The 8 GB version has room for 2,000 songs; 7,000 photos; or 8 hours of video. Need a little more space? The 16 GB nano can hold 4,000 songs, 14,000 photos, or 16 hours of video. On a single charge, you can enjoy up to 24 hours of audio or 4 hours video.

The nano's 2-inch backlit LCD lets you enjoy album art, photos, videos, and games. The accelerometer lets you turn your nano on its side and navigate through your album art with Cover Flow, share photos, or watch widescreen videos all in landscape mode.

Another bonus? Now you can get in on games made especially for iPod nano and the accelerometer. They respond to the way you move, so they're immersive, addictive, and a blast. Plus, iPod nano comes with Maze, which lets you work your way through vast mazes by tilting and moving. You can find even more games on the iTunes Store.

Finally, you shufflers will enjoy the new shake feature. Ready for the next song? Just give your nano a quick shake and it shuffles to a different song in your library. Shake it up. Start shopping for an iPod nano.

If You Want Just Music--Especially for Working Out

Available in a variety of colors, the shuffle keeps things simple. Choose from one of two storage capacities: the 1 GB version promises up to 240 songs, or you can more than double that on the 2 GB shuffle (500 songs). All models have a Click Wheel that puts control front and center, allowing you to fast-forward, rewind, pause, and play songs in an instant. It's also where you'll pump the volume up (or down, of course).

A single switch on the top lets you decide if you want to play all of your music in a random order or if you want to hear playlists and albums in the order you saved them using iTunes. All of this atop a sturdy clip that lets you take your music anywhere--without any hassle. And it's the perfect workout partner: Clip it to your shirt and go, without the worry of dropping your high-capacity video MP3 player.

Not only is the package appealing, but so is the price. Checking in at well below $100--considerably less than its screen-bearing cousins--the shuffle is easy on your pocketbook. Many find it so affordable that they use it as a second device, either for a specific purpose (maybe it's loaded with motivating music for workouts, or it could be your audiobooks-only player) or for times when you just want to clip it on and go.

Start shopping for an iPod shuffle.