Let's get this clear for once and all.
Gabe took the question to mean "Will the game be playable in the widescreen mode shown in the videos?" and of course the answer is yes as Valve have already stated that they will support native 4:3 resolutions as well as widescreen 16:9 resolutions.
THE SOURCE IS THE ENQUIRER.
(Because you're all stupid, The Enquirer is basically a tabloid so they make up most of their content. They are the ones who said it was 100% for sure that Doom 3's multiplayer had been scrapped. So although HL2 will be bundled with an ATI card, that's the only...
Of course it's optimized for ATI cards, but it's also optimized for Nvidia cards, or Matrox cards or what have you, this is why the Source engine is so flexible and able to run on vastly different hardware configurations.
What's with you people, or this site for that matter? Half-Life 2 was officially cancelled a little under a month ago, check the Valve website for the press release http://www.valvesoftware.com/press.htm