I can't speak to a all in one case but will give you my favorite combination of case /screen protecter
I have tried then all since I bought the original Iphone the weekend they came out. Now keep inmind I work in the trades and have my iPhone on job sites 6 days a week and untill I ran my 3g over with my truck ( long story) a month ago have never even scratched one.
Here's my solution
the incase slider is IMO the best hard case made. Fits great slides in and out of pocket great and you can charge it with out taking it out of the case. ( if you use a dock just dont put an adapter in and it's all cool) This case has taken 10 plus hits to the ground and pavement with out a problem.
For the screen there is not a better product then the nvisable shield from zag. It is awesome I am always puttng screw drivers and cuts into the pocket I keep my phone in with never a scratch. They are a little expensive but warrenty for life and they mean it. When I ran my phone over and had to replace it I went to zags site and they sent me a new invisable shield-free. Find the links below.
I hope this helps.
Clay
Incase: A better experience through good design.
ZAGG | invisibleSHIELD | iPhone, iPod Cases, Screen Protectors, Covers, Shields, Skins, Invisible Shield