Thoughts
"Smart data structures and dumb code works a lot better than the other way around." Context and analysis below the fold
The line before is "especially in languages like C that don't naturally do dynamic typing."
I think this idea is key. I'm frequently caught up in the strict/dynamic typing conflict. But the key is "smart" typing. Type checking things that need to be type-checked. Creating standard interfaces that allow for code re-use. Not checking properties that aren't important.
Source is still The Cathedral and the Bazaar, Eric S. Raymond, http://www.catb.org/~esr/writings/cathedral-bazaar/cathedral-bazaar/ar01s04.html