I should be more specific, though.

Machinima can be great when it's made as an integral part of an original work. For instance, I remember the ill Clan's "Apartment Huntin'" (one of the earliest machinimas) was absolutely hilarious. But what made it funny was that it was original scripting, acting, and improvising. And it poked fun at the game engine, too ("Hey, nice pool!" "But we're carrying axes.").

Taking someone else's music, and then pressing the "dance" key to get your WoW characters to run their dance loop (which someone *else* keyframe animated, by the way), and calling that an original creation worth posting on YouTube is the thing leaves me cold.