In the same way that my shelves (and sometimes my floor) are swarming with MP3 players, CNET handheld expert Bonnie Cha's desk normally features an inordinate number of PDAs. Nearly all of them can play MP3s. So why would Bonnie, of all people, have any use for an MP3 player? Why not just gas up a Sony CLIE with MP3s and extra memory and hit the road?

I can think of a few reasons why an MP3 player would still float her boat. First, Bonnie told me that sound quality is not always a high priority in the handheld world, probably because the DAC is less expensive or because of interference from the other processes going on inside a handheld. Another obvious drawback to filling your PDA's memory (which typically isn't all that large, say, 64MB) with MP3s is that handhelds are way too large to take along on a jog.

But most damning is the fact that the average PDA can play music for only about four hours until the battery runs out, thanks in part to the large, color display. Any data saved on the device's internal RAM could potentially be deleted, depending on the model, when the battery's charge fades. If you have all the info backed up to a computer, you'll only lose info entered after your last sync. You could also save your important organizer data on an inserted SD/MMC Card where it won't get zapped, but that gives you less room for music, and you'd still have to worry about whether you'd saved something important on the device's memory. Handhelds such as the Dell Axim X30 even have backup power to give you a few more hours before your data disappears. But all in all, the basic rule of thumb is that a handheld's battery is worth saving if you want your data to survive.

The core of the problem is that handhelds and MP3 players meet fundamentally different needs. That's why they each need their own dedicated battery: one inside a PDA, and the other inside an MP3 player. Two sets of portable requirements equals two batteries, plain and simple.

So back to Bonnie...which MP3 player is right for her? The first step was to ask her what she wants from an MP3 player.

Lots of storage
Bonnie has about 17GB of music on her computer's hard drive and plans to add about three albums per month. She'll want an MP3 player with at least 20GB of storage, that way her device can accommodate her growing music collection.

Voice recording
Most PDAs can record voice memos with a built-in mike, and Bonnie has found that she occasionally likes to record a quick voice memo or reminder. Clearly, she'd like an MP3 player that can do the same, in order to save her PDA's precious power supply.

Data ferrying
Every once in a while, we all need a way to get data from one computer to another without a lot of hassle. Bonnie needs something that can show up as an external hard drive so that she can occasionally work at home by dragging and dropping handheld review manuscripts and other data onto the device, bring it home, and upload the data to her Mac at home.

MP3/WMA compatibility
Bonnie's music collection exists in CD, MP3, and WMA formats. No matter what MP3 player she chooses, it'll come with software to encode the CDs. Almost every MP3 player plays MP3s (I know, it's almost as confusing as the fact that light almost, but not quite, travels at the speed of light, but...).

In-line remote
I asked Bonnie whether she could picture herself carrying her MP3 player in a bag while walking and using a remote control to control playback. She liked the sound of that, so a player with an in-line remote is the way to go. (She'll need a Hold slider to deactivate the unit's controls while it's in her bag, too, but I consider that a mandatory feature on today's MP3 players.)

Support for online stores
Can you believe that Wal-Mart sold more digital music than Napster did in March? Actually, considering that Wal-Mart sells somewhere around 15 percent (14 percent as of late last year) of the world's offline music, maybe it makes sense. Bonnie buys music online, so she'll need a player that supports some form of secure download.

But...she jogs
Bonnie's capacity requirement points toward a high-capacity, hard drive-based player. Although many people swear by it, I still maintain that jogging with a hard drive is not cool. Even if you can put up with the extra weight, there's always the risk of banging the player around one too many times for its hard drive. That's why I'm going to recommend a cheap, flash-based, ultracompact player with just enough memory for one of her jogs: "about 45 minutes."

The decision
The trick here is to look for something we've rated highly that has the right features and (this is important) doesn't come with a bunch of features she'll never use. If Bonnie has no urge to, say, convert a vinyl record to MP3 using a digital optical input, she shouldn't pay for one. I didn't ask her to rate how important design and ease of use are to her, but these days, you always have to consider the Apple iPod (the king of user-friendly design), especially in this case, because Bonnie doesn't need niche extras such as line-in recording or extended battery life. With a Belkin Voice Recorder attachment, the 20GB iPod fits the bill pretty well.

In this corner, we have the zenlike Apple iPod, clearly in fighting trim.	And in the blue-gray trunks, it's the heavyweight Dell DJ, packing more battery power, an internal voice recorder, and an extra two ounces.

On the other hand, since she's been working with a paltry four hours of battery life, maybe long battery life (not one of the iPod's many strong suits) would be a nice change. Or maybe she doesn't want to drop $426 ($389 + $37, including shipping and handling); how about the 20GB Dell Digital Jukebox DJ (currently $279, including shipping), which can deliver nearly 20 hours at a stretch. It's larger and less stylistically appealing than the iPod, but it has a voice recorder built in and would save her $147.

	Rugged design, great jogging accessories, FM radio, expandable memory, and easy-to-use-while-jogging controls--yes, this'll do nicely.

For jogging, I must insist that she pick up a flash player. If her allotted budget's already nearly maxed out by the hard drive player, it doesn't have to be a new or overly snazzy one. As long as it has decent sound, comes with an armband or a belt clip, and has at least 64MB of memory, she'll be set. The Rio S30S is perfect for Bonnie's jogs, and it costs only $63. This gives Bonnie two players for less than the cost of a single iPod, still leaving her with extra cash to spend on a sweet set of 'phones or some more music.

So that covers it. If Bonnie takes my advice, she can rest assured that the handheld's info won't get zapped, and she'll have plenty of options for transporting and listening to her music.

Associate Editor Bonnie Cha covers handhelds for CNET, and the last album she bought was Air's Talkie Walkie.