Bentler - 8:38 pm on Aug 2, 2010 (gmt 0)
In my personal experience, link fixes have resulted in better rankings, but took a month or two to show up. By fixing my problems I overtook an authority site on their keywords-- until they fixed their broken links, that is. This was before G changed to caffeine though, and the response and timing could be different now.
For a large site, you might give Maxamine a shot...works great.