Just got a Tuffwrap for mine and it arrived yesterday. I somehow ended up with a 3mm scratch on my screen just over where the call button sits in the springboard. It annoys me everytime I see it but it doesn't affect operation obviously. I toyed with the idea of Brasso'ing it out but thankfully read the warnings first. Brasso does a fantastic job on the shiny metal edging around the glass though!
The main reason I wanted a case was because I do value it particularly since it would be hard to replace if it was broken given the new iPhones and their new baseband bootloader shenanigans. Scratches just piss me off but if the case somehow protects it against a fatal fall or something then I'm all for it.
The other reason I wanted a case is kind of against the whole aesthetics of it. The iPhone's unique design lends itself to be easily recognised by the public. I've already had a few people notice it and recognise it. By having a case around it it just looks like some slim smartphone or something from a distance and not so attractive to would-be theives. Simple as that.
Either way - theft or fatal damage - at the moment would mean I'd have to go back to a normal phone until Apple start selling iPhones down under, since getting a replacement with 1.1.1 firmware would be difficult and harder to do as time progresses. I'ld rather that didn't happen. Not to mention, neither my mobile insurance nor my contents insurance would cover it (the former because Optus think I have a Motorola, the latter because it's a mobile phone and contents insurance does not cover phones. :-(
Which reminds me I might as well cancel my mobile insurance now
