I use SGP Steinheil Ultra Crystal. I think its the best screen protector I've ever used. Its clear like glass, smooth like glass, and scratch resistant like glass. Most people who see my phone don't even realize there's a screen protector on it. I've used Zagg before and I didn't like it. It has an orange-peel effect, reduces screen visibility, and isn't smooth when you slide your finger on it.
Motorola V300 -> LG Chocolate -> LG Dare -> HTC Droid Incredible -> HTC Thunderbolt -> Samsung Galaxy S III
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