Stallion -
Please don't think twice about using a clay bar on your paint. I know that you stated that you question if it's right for your car, my answer is that it is correct for every car. Even a garage queen that attends shows only, and even if that garage queen is typically a trailered car. The reason being is that there are air born contaminants that you do not see, but that do come into contact with your paint and embed themselves into it. The use of a clay bar will greatly help with this issue and will leave your finish properly prepped for the next step.
If you are still not convinced that it's for you, think of it this way: if you do not clay, what you will in essence be doing once you begin to rub on the surface (either through waxing/polishing/washing/quick detailing, etc.) is actually breaking off thos pullutants and contaminants and rubbing them right into your finish because they have not been removed with a clay bar. I don't think that those are the results that you are after.
As far as the quote offered by Richard Newton, I find fault with his statement that a wax will not add shine to a paint surface. That is a completely erroneus statement. Where is my BS flag when I need it?
And no, wax has no long term issues associated with it's use. You are correct in your assumption in regard to the repeated use of a polish and it cutting into the paint. Polishes, by their very nature, are abrasive - they remove paint with every use. Use of a polish by hand will take longer to go through the paint to an unsafe level, vs. use by machine though. I only like to use a polish on a limited, as needed basis.
As far as Zymol goes, there are 2 different Zymol product lines. One is an over-the-counter line-up and the other is the higher end, very expensive line-up. Some of the higher end Zymol products (waxes) sell for $1,000.00 and up. Gimme a break. There had been much discussion not that long ago in regard to Turtle Wax actually purchasing the lower end Zymol product line up and producing that themselves, but with the Zymol name attached. Think of Turtle Wax what you will, but in my opinion there are far better choices out there. The Zymol products that you see at the local PepBoys, AutoZone, etc. are a bit lackluster in their performance in my opinion. Save your money.
You question whether or not you need a wax or a polish - I say both. You will first want to polish, and then wax. Remember, wax is always a finishing step.
81NMVETTE - You state that you live in a climate where the sun is very unforgiving. You feel that a wax would be your best choice, but I have to disagree. Waxes suffer from a low fracture point. In weather such as yours, a wax would stand very little chance of protectiong your paint. Both melting and evaporation of the wax would be issues for you, especially on a car that sees a good amount of road time. A better choice for you would be a quality polymer. These do not melt/evaporate and offer several months of protection without reapplication.