FWA (Favorite Website Awards) has launched a Flash-based video theatre to highlight "the most creative videos from around the world across a range of categories including: Hot Advertisements; Show Reels; Game Trailers; Motion - 3D - VFX; Animation; Virals & Various; Movie Trailers, Exclusives & Featurettes." In other words, it's aimed more at the commercial business than the typical YouTube scavenger. But if you want to watch an Iron Man trailer again, Coke's Happiness Factory advert, or Dvein's showreel, it's the place to go.
Search doesn't work yet, but there are not so many videos that you can't scan the index.