From Firingsquad:

With all the DOOM 3 news lately, I thought it would be a little different to mention the second big shooter on most gamer's minds this year: Half-Life 2. IGN has posted their impressions on the game, based on a hands-on demonstration over the weekend. Included in the article are the minimum system requirements, which are a 1.2GHz CPU, 256MB RAM, and DX7 graphics card, while the recommended system is a 2GHz CPU with 512MB RAM and DX9 graphics card. One other interesting note mentioned in the article "Doug specifically stated that the ATI x800 was the card of choice amongst many of the testers, as it ran roughly about 30% faster than Nvidia's best cards."