ExtremeTech tested Windows Vista Beta and reports that World of Warcraft runs smoothly with no hassle off the box except for a small cons. The quote originates from page 3 of their article.
ExtremeTech: “Blizzard’s enormously popular massively multiplayer RPG, you’ll be happy to know, works just beautifully under Vista. There are no funky workarounds needed to deal with non-admin user accounts, performance seems just great, and it even runs just dandy in a window. It currently doesn’t add itself to the Games Explorer, but that’s about it.”