Skip the service plan. With a few exceptions the car won't require anything but oil changes or a few air filter changes you can do yourself in that time. It'll require 10 oil changes (if you use dinosaur oil) or 5 if you use a good synthetic. That's hardly worth $1800+ dollars.
As for the warranty, you can get it considerably cheaper elsewhere. Email TDietrich@FactoryDiscountWarranty.com
He works for Toyota of Greenfield in MA. (Any Lexus or Toyota dealer can sell you the same warranty)... you should be able to get the 7 year/100 k warranty for at least a few hundred less than you're being quoted for the 75k one.
As to the warranty being worth it, if you plan to keep the car that long I think it is, doublly so if your car has expensive-to-fix options on it (Nav, ML, Adaptive cruise, etc)
Great information. Thanks very much!