what amperage alt should i run?

I have been told by the local guru that 65 amps is plenty unless your getting way up into all the fancy accessories like power windows, seats, sun roof etc etc etc, electric fans are a big draw but will jive ok as long as EVERYthing is wired correctly. The newer ones comming off the assembly lines today are up to 120 amps but hell they have 110V power invertors in em and plenty of outlets to plug laptops into, front and back and onboard computerized everything.