Our XT720's screen is made of Gorilla Glass, which is very hard and scratch proof. So, unless you'd like an anti-glare (another word for matte) protector, you won't need clear or whatever. As Sorhab said, screen protectors are made of plastic and can easily be scratched.
Only matte screen protectors are fingerprint free. Even that, you still need to wipe it with mild soap-liquid at least once a month to clear.
All animals are equal, but some animals are more equal than others.
Daily driver: HTC One S (Stock ICS 4.1.1 with Sense 4+), Toshiba Thrive 7" (Stock 3.2.1 Honeycomb ROM)
Primary Backup: Motorola Atrix4G (CM10.1)
Secondary Backup: Acer Iconia Smart (Gingerbread 2.3.3 stock ROM)
Siemen C28, Samsung A800, Nokia 5300, SE W580i, HTC Jade, Samsung Jet,Moto XT720