How do you take down a Juggernaut?

In my time of playing the multiplayer, I've noticed the Juggernaut kill streak makes someone nearly invincible, especially if two people do it at the same time. Now my question is what is the best way to take these people down? Just keep shooting? Are there any particularly good techniques to kill them quickly? (or at least keep them from killing your entire team twice)

Even with Juggernaut players are still very vulnerable to headshots (due to the damage multiplier). Most headshots 'overkill' a player so you never really realize how much more damage they actually do.

To deal with a juggernaut: crouch behind a box, wait for them to walk by and stick a semtex to them, knife them, or (the most reliable) repeatedly shoot them in the head.

Sustained high damage is the key.

Juggernauts heal fairly quickly, so you have to keep up the damage.

Explosives help a lot, but the main thing to do is to make sure they're never getting a chance to heal up. Do this by keeping yourself alive to continuously fire at them, or fire at them with a team mate.