Have you tried upping the quality you are watching in? When I had those issues (TW, 10/1) sometimes it actually helped to watch in 720p instead of 360p. Makes no sense, but whatever (may have been a firefox issue with saving tabs, which I also fixed recently, or that weird OpenDNS-youtube path issue).
Yeah, it's infuriating to have that much speed and still be unable to watch youtube normally.
