I just got a speck case for the ip4. I just got it so I would have some protection while waiting on the otterbox to come out. I really like this speck case though. Fits very snug and it doesn't add a lot of bulk to the phone. I probably paid more than I needed to for it since I bought it at an AT&T store ($35), but over all I am very happy with it. I like it enought that I may not get the otterbox now. I am sure however that the otterbox would provide way more protection. I think this Vapor case is bad@$$ too, but I can't justify spending $80 - $100 on this right now.
http://www.elementcase.com/iphone4.html