5. Fill It Up

If you're installing applications, taking your whole address book with you and synching email, you need space on your smartphone. You'll never get a message saying you have to delete a few text messages to receive an SMS that's waiting for you, but a large music collection or a complex application like GPS navigation will need plenty of memory.

Samsung's i310 is a Windows Mobile Smartphone with an 8 GB hard drive and even the 4 GB of flash memory in the new Sony Ericsson W950 is as much storage as many MP3 players. But most devices only have flash memory, some of which is already in use for built-in applications; a Windows Mobile Smartphone with 64 MB of memory will usually have 25-30 MB available for your apps, for example. Even though smartphone applications are far smaller than PC apps you can still run out of space, so look for a device with a memory card slot.

SD is getting smaller and smaller, but you can still use MicroSD and MiniSD cards in full-size SD slots with an adapter.

MiniSD and MicroSD cards are widely available and far from expensive: under $20 for 512 MB and around $40 for 1 GB at the time of this writing, and less if you shop around. They usually come with an adapter so you can use them in a standard SD socket; handy for transferring images back to your PC. Sony Ericsson and Nokia usually use their own memory card formats, Memory Stick Duo, Memory Stick Micro and RS-MMC (although the Nokia N75 uses MicroSD). These smaller versions of Memory Stick and MMC cards tend to be a little harder to find and more expensive.

Even feature phones like the LG Chocolate are starting to offer MicroSD and MiniSD slots. It's more convenient if you don't have to take the battery out to access the memory card.

Check the location of the memory card slot. It's far easier to get to cards if the slot is on the side or the base of the phone, but smaller and slimmer phones often save space by putting the slot under the battery or even under the SIM.

Windows Mobile smartphones include persistent storage so you won't lose data or applications even if the battery is completely drained.