The Griffin Survivor is very much in the mold of the Otterbox Defender Series, with an integrated screen protector, but some people prefer the Survivor. Needless to say, this case is pretty chunky, but build quality is very solid and it's rated to protect your iPhone from drops up to 6 feet. While it offers some water resistance, it's not waterproof. It's also available in military olive and pink.
For those looking for something less bulky, Griffin also makes the Protector, a more basic case that's made out of thick silicon and retails for less than $15 online.