Well, I purchased the extended warrenty for my 09. (I believe I paid $1750?)
Figured I'm not going to mod the car (other than some led bulbs, easy to swap out if nessesary) and I tend to keep cars a long time (8 to 10 years) and with all the electronic gizmos in the 370 it helped give me some peace of mind knowing that most of those items will be covered for at least 7 years/70k miles.
A copy of the flyer on what the warrenty covers is on Nissan's site:
http://www.nissanusa.com/pdf/owning/Gold.pdf