I put an Invisable Shield on mine last night. I can tell it is there and the cost is a bit much IMO, but I have no bubbles or any other problems, and if it saves me some scratches down the road, then I am all for it.
I got one of the protectors sold at Zagg and tried it on my droid for about a week, it seemed to cut down on the smudges on the screen but it was harder to clean off when they did appear. I ended up removing it because it started to get small indents in the film from something in my pocket (was not keys, only thing in there was a plastic pull cord in the jacket). If the screen is really glass and not plastic I don't think there is a need for any protection unless you keep diamonds in your pocket