The world’s largest PC company just launched a “media tablet”. Conflating the iPod Touch and iPad brands into “TouchPad” HP joins RIM in announcing an integrated OS/device product to compete as a platform vs. iOS and Android (and to some degree even against Windows).
There are others waiting in the wings. Presumably, Microsoft is hard at work to release a tablet-compatible Windows sometime near the middle of this decade. MeeGo is also going through its gestation period targeting Atom-based tablets. John Gruber notes the excitement around tablet platforms in his article about this post-PC renaissance in computing alternatives. I also noted that the end of the PC era was marked by the end of WinTel at CES.