Thats up to you because I've never felt a need to. Best Buy's is nice because when my roommates Beats headphones broke they basically give you the price you paid (lets just say $300) and then add in the insurance (I don't know the real price but lets say $20) they just basically gave him $320 gift card to use on anything. Which would be nice for consoles if price drops you'd get extra $.
I wouldn't. I say stick to the 1 year warranty. The 2 most likely scenarios are either the hardware won't be an unmitigated disaster like the 360 was at launch and so you won't need the longer warranty or it will be an unmitigated disaster in which case they'll likely extend the warranty for free.