DHH reviews, refactors and shows BaseCamp code.

"The best programmers are the ones who write the most legacy software. The best programmers are the ones who learned the most from their projects and go on to be better and better."

The second bit is true. The first bit is almost certainly not. DHH makes some good points in this talk, but it sure seems as though most of his experience is on projects that he either started or was with from the early days, and that he's been spared the pleasure of working on codebases where 'svn annotate' shows names of people who have been gone from the project for years.