Well the screen is glass, so it's fairly resistant to scratches. The screen would crack if you dropped it onto a hard surface, but the biggest problem you'll have with an iPhone 3G (and touch) is the fingerprints.
The Touch has the kickass chrome back, but it scratches very easily. They remedied this to a degree with the iPhone by using plastic, but it doesn't look as cool.
There are literally hundreds of cases to choose from... mostly hardshell types which leave the screen exposed. Since i would never use one of those sticky plastic screen protectors, i opted for a soft(ish) leather case which covers the whole thing. It bought it in the Apple store and it's been ok, but it has a velcro strap and the velcro isn't working so well now.
I'm going to get a case from Vaja i think. Their range is supposed to be amongst the best you can get... although the involution SP Top (?) is expensive (around $80) for what it is. But i haven't seen any other flip top cases that i would consider buying, and there will be very few people with them over here, so i'm going to order one and see what i think.
There's a review of the case i'm looking at
HERE and the Vaja website can be found
HERE :)
iLounge has a lot of case reviews, and there are some good alternatives available, but it depends what you want really.
<message edited by Nitro on Sep 25, 2008 08:34>