I am a LifeLock customer and so I follow developments in this arena pretty closely. Check this post LifeLock and Identity Theft from Schneier on Security:
LifeLock does a bunch of other clever things. They monitor the national address database, and alert you if your address changes. They look for your credit and debit card numbers on hacker and criminal websites and such, and assist you in getting a new number if they see it. They have a million-dollar service guarantee -- for complicated legal reasons, they can't call it insurance -- to help you recover if your identity is ever stolen.All in all, I probably will remain a customer. Schneier does a good job basically saying that LifeLock is clever and useful but too expensive. That's more positive than the press they've been getting.