It sure does sound like you're using the open source nv driver. World of Warcraft requires the proprietary nVidia drivers, at least 178.24 for your card. see this page (http://us.blizzard.com/support/article.xml?articleId=21085&categoryId=2332&parentCategoryId=2316&pageNumber=1) for card and driver compatibility. You may prefer the Debian Way (http://wiki.debian.org/NvidiaGraphicsDrivers) for installing drivers. See also this howto (http://wiki.debian.org/NvidiaHowTo). Debian is up to 177.80 in the Lenny and testing repos. Debian Sid is at 180.20 if I am not mistaken.
