My general rule for buying extended warranties is if its a mobile device (laptop) then use, desktop, no
In the years that I've had my MBP, I've had the following replaced, all for free, for the cost of Apple Care:
1. New charger (old one had wires beginning to come out towards the unit)
2. New Hard Drive (seek levels were off and I was experiencing frequent lockups)
3. New Glass Track Pad (I was getting odd double clicks and triple clicks)
4. Another new charger (I was used to the old Mag Safe chargers and had a case that was messing up the magnetic part)
5. Hinges/Screen (Hinges were getting loose. I honestly didn't need to do it, but figured I might as well. The screen is required to be replaced by Apple when they do hinges.)
All in all, the parts themselves paid for the warranty, not to mention the ridiculous labor charges I saved. Granted, I could have done the work myself without the warranty, but really for the chargers alone, it has been worth it.
My other MBP has also had two Mag Safe chargers replaced. Each time I have gone to have real work done (not the chargers being replaced) it has only taken 24 hours to get my machines back. I'm not sure what everyone's experience is, but mine has been excellent. I will never not purchase Apple Care.