Trident also makes a ruggedized case for your phone. The Kraken!
http://www.tridenteer.com/categories/HTC-EVO-4G/
I got one for my new Droid X and love it. Makes the phone bigger but I think I can drop it off a roof without hurting anything. I checked the reviews of it vs the otter box and the kraken seemed to rate better. All the speaker holes are covered with cloth so they keep dust out better. Plus you can get it in different colors.
This droid is the first phone I've had insurance on. In my line of work (HVAC) I can be tough on phones and that exposed screen is very vulnerable. Will see how long it takes to destroy it. Found out last year in Moab that an iphone will sort of survive being run over by an amigo on 37's lol. Dont remember who's it was but Corbin ran over it. Screen was broken but still worked.