difference between InvisibleShield, Ghost Armor, Clear Shield

Do you really need screen protection? I dont think so
Check out this video
http://iphoneindia.gyanin.com/tag/screen-protection/

From a novice point of view, there is no difference.

Commercial companies fabricate the same exact way of story for years to make the product so cool to use. As you say "used to protect the leading edges of military helicopter blades from wear and tear" is the same as "We've imported diamonds from the South Africa mining facility heavily guarded by the top best paramilitary troopers to bring you the best African diamonds." or whatever the story Mervis Diamond importers goes by.

Simply put, they are all the same. Pick one you wish to use. The cheapest will do. If you want to pick one without a screen protector, go to IvySkin.com and they sell shells that cover the entire iPhone and the screen itself. They sell Xylo brands that cover the entire body.

Absolutely Joe.. There is no different.. Its just some kind of a marketing gimmick..
you dont need one. I have been using 3G from last 5months now and I dont have any scratch on my screen. I just make sure that I dont put my iPhone 3G and keys together.

Let me tell you why you DO need a screen protector.

I had a Dell AXIM for 2-3 years. Used it with an awesome screen protector (i can't remember the name, it's a static cling, washable, reusable film). I had it on the device from day one. I didn't smudge and I never had any problems until the day I dropped the device face first on a pebble getting out of my car. The protector had a dent and I thought the screen has a chip. I peeled the film of to reveal an immaculate screen without any scratches.

Now, on the other hand, I have an expensive watch with a scratch resistant glass. I dropped that by mistake and it his something on the concrete and I had a very expensive dot on its face. Now, I don't expect anyone to use a screen protector on a watch but if $10 will maintain an immaculate screen i think it's worth it.

Now, If I just could find the same screen protector I had on my AXIM I would buy it in an instant. It was smudge resistant too. I'm on my 4th cheap film and they either smudge or they are sticky.