End of WWII: 20 July 1944?

A while ago, I read a book about the wives of the men who made an attempt on Hitler's life on the 20th of July, 1944. And recently I watched Valkyrie, a Tom Cruise movie about the attempt. I can't help wondering how different history would be if the attempt had been successful.

What would it be like if we could teach our children, "And that's when Germany ended the war and solved its own problems"? Would Germany's reputation after the war have been completely different? Would Germany have been able to more quickly pull itself back together economically? So many questions . . .