I had (just sold it to a mate) a version 1 iPhone since its arrival in UK and, whilst i managed to scratch the chrome bezel and dropped it a few times, I never managed even the tiniest scratch on the screen. I think the glass is of decent watch quality. I've even run a key across it to impress others (sad).

I suppose it must be 'possible' to scratch it but ...

I've seen a few that have shattered on impact with the floor. Amazingly the touch bit still works fine.