If you use a CD walkman for your portable music needs, you're part of a shrinking majority. The popularity of PCs and the availability of digital music files has made the choice a no-brainer for many music lovers. Digital music files can be stored on your computer in a number of formats. The most common are MP3 and WMA. The main difference between these formats is the quality of sound in relation to the size of the file. For CD-quality sound 128mb/s is an acceptable standard. The MP3 format, although the most popular, needs the most space to store great sounding music. Many, but not all, players accept both file types. There are basically two options when considering a MP3 player: hard drive or Flash-based. A hard drive-based player is just what the name implies -- a portable hard drive. Data is stored and read from a spinning disk inside the device. These currently range in capacity from 1GB to 30GB. Most double as a secondary storage unit for your PC when connected. Flash-based players are much smaller and contain no moving parts -- using flash memory to store files instead of a hard drive. They hold anywhere from 64MB to 512MB of music. A popular size, 128 MB, holds approximately two hours worth of MP3 files. Flash players come in a variety of tiny packages and most can easily fit in a pocket with room to spare. FLASH PLAYERS Co-Won iAudio CW-300 Capacity: 128MB Pros: Stylish compact design, FM-radio play and record; Advanced sound settings Cons: Not expandable, plays only MP3s This well-designed device is an update to the adorable and well-regarded CW-200. It keeps all of the features of its more diminutive sibling, while adding one major improvement -- battery life. The addition of a single AA battery (rather than the AAA of the CW-200) increases battery life from about 12 hours to around 30 hours. Although this device plays only MP3s, which limits you to two hours of music, it handles them deftly. The CW-300 also includes an FM-radio and lets you record from the radio, which is a nice way to add a tune or two to the mix. If you're looking for a small MP3 player with big sound this could be the player of choice. Available in 256MB capacity (www.jetaudio.com; $239). Pogo RipFlash DX Capacity: 128MB Pros: Records directly from CD player; expandable memory Cons: Mediocre button layout RipFlash DX has enough features to satisfy and a couple of extras that make it appealing. The ability to record directly from a CD player makes this unit stand out. Just plug the included cord into the headphone jack of your CD player (or any other digital music source) to record WMA files directly to the device. The tracks will appear by number rather than name, but it's an easy way to add more music on the go. Add additional storage capacity by purchasing a MultiMedia/SD Media Card (about $50) that slides into a hidden slot. The RipFlash plays both WMA and MP3 files. Sound quality is good, but not great. This little player had us sold at the word "record" (www.pogoproducts.com; $129.99). Creative Nomad MuVo Capacity: 128MB Pros: Easy to setup and use; doubles as a USB storage device; Tiny Cons: No equalizer or play settings The MuVo is a study in the art of simplicity. It needs no cables, no drivers, and no set-up disk. It is a cleverly designed player that plugs directly into the USB port of your PC. Once attached it appears as a removable drive in your windows explorer. From there you're just a drag and drop away from dancing in the streets. There is a setup disk and even a booklet, but there's hardly a need for either. However, you do pay a price for all this convenience. There are no advanced volume settings such as treble or bass. The beauty of this device lies in its ability to strip all of the complexity out of getting music files into your hip pocket (www .creativelabs.com; $129). HARD DRIVE-BASED PLAYERS Archos Jukebox Recorder Capacity: 20GB Pros: Can record MP3s directly from analog or digital source; good sound quality Cons: Unattractive design; huge Carrying 20GB of music around in your pocket is no mean feat, but it shouldn't be quite this hard. Size is this device's biggest drawback. Not only is it too heavy to fit in the pocket of anyone but Shaquille O'Neal, but four huge black rubber bumpers on each corner add extra bulk. Still it's what's inside that counts, right? For starters, the Archos Jukebox recorder has plenty of space and great sound quality, which will let you tune out naysayers. Like most other hard drive players, the files can be browsed by artist, title, or play list (which can be created either on the PC or on the device itself). You can also add MP3s on the fly through its real-time MP3 encoding capabilities from either an analog or digital source. So you can finally convert those old scratchy albums into old scratchy MP3s. Unfortunately, this device started exhibiting problems after only two hours of testing. First, the unit froze during play and could be restarted only by turning the device off and on again. After several tries the unit cut off completely during play. Once the unit recharged the problem disappeared; but we were still wary. All in all it's a functional MP3 player; just don't expect any bells or whistles (www.archos.com; $269). Creative Nomad Jukebox Zen Capacity: 20GB Pros: Well designed, sleek, excellent sound quality and options Cons: Occasionally clunky interface The Jukebox Zen is well designed and well appointed. The unit can handle both MP3s and WMAs and lets you hunt down music by artist, song, playlist, album, or genre. The Zen also lets you edit tracks on the fly. You can even create multiple playlists directly on the device. Alas, it is a more complicated process than would seem necessary, but it does work. But you'll forget about the occasionally clumsy interface when you hear the sound; it's truly zen. Creative has relied on its considerable experience in the sound processing arena to provide excellent sound options. There are numerous digital signal processing options including the ability to simulate different listening environments. You can also change the quality of sound by selecting a spatialization option or compensate for external noise using Smart Volume. There's even a time scale function that allows you to change the speed of a song. The Creative Nomad Jukebox Zen has enough features, settings, and sound quality to make it almost possible to hear the sound of one hand clapping. Also available in 60GB version (www .creative labs.com; $299). Apple iPod Capacity: 15GB Pros: Excellent design, intuitive interface, good sound quality Cons: Can't delete tracks on unit; MusicMatch software for Windows needs an update The iPod creates an emotional reaction as soon as you lay your eyes on it. It is without doubt the smallest, lightest, and most elegant hard drive-based MP3 player available. There is only one moving part on the iPod, the hold switch, which keeps you from accidentally pressing one of the immobile function "buttons." It's a good thing because the buttons and scroll wheel are incredibly responsive. Set-up was easy but not problem-free. While Mac users have the tightly integrated iTunes software to control syncing with the iPod, Windows users must deal with MusicMatch 7.5 to sync with the iPod (A Windows version of iTunes is due out at the end of the year). At first, MusicMatch and the iPod worked well together, but shortly thereafter the software would not recognize the unit. The problem was fixed easily by downloading a patch from www.music match.com. Windows users will appreciate the $19 USB/FireWire adapter that eliminates the need to purchase a FireWire card to connect the device to your PC. The iPod is available in 10GB and 30GB sizes (www.apple.com; $399 for 10GB iPod).