BlackBerry PlayBook

RIM's has a smaller 7-inch display, but it also weighs in at less than a pound. It does not run the BlackBerry OS, but is built instead on the QNX OS. It has 1GB of RAM, a dual-core processor, dual HD cameras, HD video recording, and HDMI output. The PlayBook is also quite versatile--able to play both Apple and Microsoft proprietary audio formats, and supporting both Adobe Flash and HTML5.

HP WebOS Slates

Details continue to leak out on codenamed Opal and Topaz. The Opal is a 7-inch tablet, while the Topaz is a more iPad-like 9-inch version. Based on leaked images, it appears that the tablets will have at least a front-facing camera, and a micro USB port.

These HP tablets also have the advantage of running WebOS. Despite the fall of Palm, WebOS is actually a very capable mobile OS and possibly offers the most formidable challenge to iOS when it comes to a tablet UI. HP has a media event slated for February 9 where it is expected to announce details of these tablets.