Mobile Technology Looks like it\u2019s back to the basics for mobile device manufacturers. According to a survey by market research company TNS, what users want most isn\u2019t bigger displays, better graphics or even limitless coverage areas. They want better batteries.Seventy-six percent of users in the United States responding to TNS\u2019s survey rated two days of battery life during active use as the most important feature of the future converged device\u2014a device that combines a mobile telephone and PDA with e-mail and other business applications. Next on the list is a high resolution camera and video camera, followed by full versions of Microsoft Office applications and 20GB of memory. Rounding out the top five: a global positioning system.