I guess one of the things that has many of us cheering today, is seeing lots and lots of slide out QWERTY Windows Phone 7 devices become official on today’s launch. Such is the case of the LG C900 we caught a couple of months ago, which today gets official as the LG Quantum.

The Quantum sports a landscape slider QWERTY keyboard, triband HSPA (850 / 1900 / 2100MHz) so yeah, AT&T will be the launch carrier. As for storage, we’ll finally see something compelling at 16GB of storage, a 5 megapixel camera with 720p video capture, a 3.5-inch WVGA display, and the typical 1GHz Qualcomm Snapdragon core.

It’ll start at the typical high end smartphone price of $199.99 when released in the next couple of weeks.