Lumia 900

The Lumia 900, which will make its debut on AT&T in the coming months, features a 4.3-inch AMOLED display (with 800-by-400 resolution) and 4G LTE support, along with a 1.4GHz Qualcomm Snapdragon processor.

The Lumia 900 uses the same polycarbonate unibody design as Nokia’s Lumia 800 and N9.

The HTC Arrive now runs Windows Phone Mango, an update to the platform with hundreds of new tweaks and features. Unlike rival smartphone platforms that offer grid-like screens of applications, Windows Phone consolidates applications and Web content into a series of subject-specific Hubs (such as “People”).

HTC is following up the Titan, shown here, with the Titan II, a 4G LTE-capable device slated to appear at some future point on AT&T.

Nokia’s Lumia 800 is another of the Finnish phone maker’s higher-end smartphones, and is designed to help it retake market share from aggressive competitors, such as Google Android and Apple’s iPhone.

Nokia’s Lumia 710 is aimed more at the midmarket, with a 3.7-inch screen and 1.4GHz Snapdragon processor. It will appear Jan. 11 on T-Mobile for $49 with a two-year contract.

Unlike Nokia, which has essentially bet the company on Windows Phone, companies like Samsung and HTC (whose Radar is shown here) also have devices running the popular Google Android platform.

Other companies besides Nokia are also aiming at more of a midmarket audience, including Samsung, whose 3.7-inch Focus Flash (featuring a 5-megapixel camera and 4G LTE connectivity) is being sold by AT&T for much cheaper than some comparable smartphones. ??í

Microsoft and its hardware partners have been unveiling a number of next-generation Windows Phone devices at CES. Microsoft’s hope is that the show can help re-launch a brand that’s attracted solid critical reviews but relatively anemic sales.

Microsoft envisions Windows Phone as an increasingly integrated part of its overall product ecosystem, interoperating with Xbox and possibly other platforms, and embracing the same “Metro” design aesthetic as Windows 8.??í