Not a speed-run, but this Zero Punctuation-style rundown of Modern Warfare 2 provides a Cliffs Notes to the story for those who bought the game just for the multiplayer. For those who bought it for the singleplayer, bigtime spoiler alert.
That means don't press play if you don't want all the story highlights, plot twists, outcomes and the conclusion. Otherwise spend a minute on this and then get back to your Search & Destroy and your perks grindin'.
Modern Warfare 2 in 60 Seconds [YouTube]