I've heard a lot of claims regarding calibrations, but that has absolutely no merit.
However, that said, a professional calibration will set the colors to a very realistic setting and may provide benefits. But most people calibrate their own sets to their own preferences, and many even use C|Net's HDTV Picture Settings forum for suggested settings.
You can check out your model's suggested settings here:
Unless you're absolutely set on having "exact" color reproduction, these settings will allow you to have calibrated your set yourself, have a beautiful picture and... thanks to C|Net, it's free.
The Geek Squad at a local electronics store says my new tv must be professionly fine tune or its life cycle could be reduced by as much as 5 years. Is this just a money thing or does it have merit?