Mobiles can come equipped to play movies and TV, but that puts a lot of strain on your eyesight, and their data storage capacity.
Music phones are emerging as the quality players in mobile entertainment.
Some of the models on show at Europe's largest mobile phone show, 3GSM, already look slick enough to nudge MP3 players off the shelf.
The secret of their success is that phones can now become mass-storage devices, using tiny, removable memory chips many gigabytes in size that can take thousands of tracks. Some have embedded memory that can hold yet more.
The relentless pace of technology innovation means those storage capacities are only going to grow.
Dan Inbar from computer memory maker SanDisk said: "In the past, the doubling of capacity has been every 18 months. Now it is coming down close to 12 months.
"Of course the other side of that is the applications that go with it. Currently the applications are running very, very fast as well."
Music on your mobile is about more than just a phone with room for more than just the top 20. The owners of music phones really want the ability to download songs when they are out and about.
Lots of companies are lining up to offer these sorts of services and while they jockey for position they know there is an elephant waiting in the wings: Apple's iTunes.
Apple's previous foray into phone music, the Motorola-designed Rokr, could not do mobile downloads; the recently announced iPhone, while not yet on the market, should.
UK-based Omnifone is offering a download subscription service which it is promoting as a cheaper and fresher alternative to what it says may come from Apple.
"Apple's business is an Apple-centric solution," said Rob Lewis, head of Omnifone. "Steve Jobs wants to be centre stage of hardware and digital music sales.
"We believe that together with 23 mobile operators and all the other manufacturers - who are already creating a billion devices every year - we can create a really compelling alternative for consumers that gives them the freedom to play and download music wherever they want on whatever device they want to buy."
The figure of a billion phones a year is the reason everyone is so interested in music phones and downloadable tracks, not least because the number of MP3 players knocking around is a fraction of the number of mobiles.
But there are concerns about cost. Consumers already complain that downloads to mobiles are overpriced and come with some hefty hidden charges.
Andrew Bud of the Mobile Entertainment Forum told us: "We have to give consumers confidence by making the pricing transparent. Customers have to know what they are going to pay when they buy it.
"Today that is not the case, because today they can buy a full track download for £1.50 or a couple of dollars, but in many territories they will be charged an additional amount of money that is not clear and sometimes may be as high as £20 ($39) for the data download charges associated with that. And that's a real problem."
Music phones look all set for take off but, as always, buyers beware.
As you are weigh up the pros and cons of which phone to buy and how much memory to install for downloading on the move, be sure to read the small print of your phone contract first.
Do that and these phones could put a skip into all our of our steps.