Straight from the horse's mouth; Half-Life 2 has gone GOLD and will be in stores on November 16th:

Vivendi Universal Games (VU Games) today announced that Half-Life® ,2, the sequel to one of the most critically acclaimed PC titles in gaming history, will ship to retail outlets around the world in November. The Company confirmed that Half-Life 2, developed by Valve Software, has gone gold with a planned retail street date of November 16, 2004. The countdown to the highly anticipated retail street date has begun around the world, as VU Games completes plans to ship localized versions of Half-Life 2 simultaneously in English, French, Spanish, Italian, German, Traditional and Simplified Chinese, Korean, Thai and Japanese.