If you would rather stick with AT&T and aren't into the new Droid offered today by Verizon Wireless, Amazon has two awesome deals for AT&T Windows smartphones. Both the HTC Tilt 2 and the HTC Pure run the latest Windows Mobile 6.5 OS.
You can get the new HTC Tilt 2 for $149.99 with new service plan on Amazon.com or the HTC PURE for only 1c with new service plan on Amazon.com.
AT&T launched the HTC Tilt2 in October and it actually still costs you $299.99 after $50 rebate when you buy it through AT&T.
The HTC Tilt2 has a 3.6" touchscreen display, a sliding QWERTY keyboard, 512 MB of internal memory, and the ability to accept up to 32 GB SD cards. It has Bluetooth, a 3.2 MP camera, and up to 8.5 hours of talk time on one charge of its 1500 mAH battery.
More details on the Tilt 2 deal on Amazon.com.

The HTC Pure was announced in early October and sells for $149.99 after $50 mail-in rebate with contract when you buy at AT&T. To just pay 1c is a great deal.
Leveraging HTC's TouchFLO 3D experience, the all touch screen HTC PURE offers a touch experience that is optimized for one-hand use, which further evolves the compact smartphone design.
Incorporating a 3.2-inch WVGA touch screen, the HTC PURE is crafted to fit into the hand and accentuates one's sense of style. With a crisp advanced five megapixel auto-focus camera with video capture, expandable memory, gravity sensor and an ambient light sensor, the HTC PURE brings many smartphone features in a compact size.
More details on the AT&T HTC Pure deal can be found on Amazon.com.