Search the forums. Plenty of threads about cases...but...
Seidio Innocase II (good all around protection)
Seidio Innocase Active (a little better protection than innocase ii, slightly thicker, better fitting)
Seidio Innocase Rugged (like an Otterbox)(comes with Innocase II, rubber skin, and plastic exoskeleton)(very durable, covers ports and camera)
Case Mate Barely There (bare bones protection, but very thin and doesn't add bulk to the EVO)
Those are what I can think of off the top of my head. Other forum members have posted reviews on most of these so like I said, search the forums.