Hi I have recently got one of these cases and think it is really good. I think it will provide lots of good protection! Highly recommended. It is not cheap but very good quality.

http://www.case-mate.eu.com/htc-One S-tough-cases-black.html

I also fitted InvisibleShield screen protector which will give great protection from scratching but its taking me a while to get used to the "sticky" feel of using it (instead of smooth glide of the gorilla glass). It also has "orange peel" texture and it quite reflective.

The other case that I had looked at was the Otterbox Commuter case but I could not find that locally. That case also looked like it would give pretty good protection too.

Another, mentioned by another member here, is this one:

http://www.amazon.com/gp/product/B005I577W6

Mine was £24 from Carphone Warehouse in UK

well i had chance to test it today! pleased to say that it passed with flying colours

dropped from from waist height onto tiled floor and it landed face down. no damage. so pleased i bought it!