The Software Maintenance blog entry on Peer Review outlines an example of bad code being eliminated during code inspection. This team has an advantage over average software development teams. They regularly conduct code reviews. It seems to happen for every bug they fix.
Sometimes it is not enough for software to perform correctly. You also want the implementation to be clean. Most software spends many years being maintained. It is not success if you hack together something that will cause a disaster later.
The goal of code/peer review is to improve the quality of the code. This may involve detecting subtle bugs. It may also mean that the code itself is improved. Once you get to that level, you have a better chance of producing that high quality code.
A Little Bit of Crypto - I have been trying to figure out to "collision resistant" some of these standard hash functions are. It is a tough concept to get my head around. I figure...