The best mobile devices for both business and personal use

As the one device you always have with you, it has to function at work, at home, and on the go. These five do it best

I'm confident that 2010 will go down as the year that personal and professional computing officially merged, as the iPhone finally knocked down the wall that had kept the two separate. Sure, working at home on personal PCs had already put holes in the structure, but it was the iPhone that took the barrier out completely.

What is the best mobile device for the new, integrated world? There are many, many options available from Apple, Research in Motion, and Hewlett-Packard's Palm division, as well as Microsoft's Windows Phone 7 and Google's Android hardware partners. InfoWorld.com has winnowed down all of these choices to the handful that matter.

[ InfoWorld picks the best office apps for the iPad and the best office apps for the iPhone. | Keep up on the latest mobile technology with InfoWorld's Mobilize newsletter. ]

Best touchscreen smartphone: Apple iPhone 4
InfoWorld has tested the iPhone against every business-capable competitor, and no one has come close. The iPhone excels at apps of all sorts, as well as Web surfing, email and other messaging, and media presentation (music, movies, TV, books, and so on). With iOS 4, it offers business-class security and management capabilities, breaking the BlackBerry's stranglehold in this arena. Only the defunct Windows Mobile joins iOS and BlackBerry OS as business-class.

The iPhone's use of iTunes, though disliked by IT, also ensures an easily accessible backup of all apps, media, and even document files. These backups can even be encrypted to comply with government regulations on managing personal information.

The iPhone 4 is not perfect. Its weakest aspect is its phone; users regularly complain of dropped calls and poor audio. It's also tied in the United States to the worst network (AT&T's). Both weaknesses ultimately need to change, and they're barriers for many people to buying an iPhone, as is the lack of a model with a physical keyboard.

But no other device comes close to the iPhone 4 in the ability to serve as a pocket computer, which is the "smart" in "smartphone."

If the AT&T tie-in or the poor phone quality issues prevent you from going for an iPhone 4, our recommended touch-only runner-up is the HTC Droid Incredible. Note that the device runs Android OS 2.2, which is not as secure as the iPhone and may not be allowed onto many corporate networks -- or at least not without a third-party software solution such as NitroDesk TouchDown or Good for Enterprise.

Best keyboard smartphone: RIM BlackBerry Torch
The BlackBerry has long been the de facto smartphone standard, thanks to its messaging capabilities. Many executives use the BlackBerry as their primary device for conducting business via email, but RIM's devices have not been good with apps, the Web, or media presentation. The company's first attempt, the Storm, was a poorly designed iPhone clone, and the Storm 2 was little better.