Writing efficient user interfaces is the main maxim, here at Vimperator labs. We often follow the Vim way of doing things, but extend its principles when necessary.
Towards this end, we've created the liberator library for Mozilla based applications, to encapsulate as many of these generic principles as possible, and liberate developers from the tedium of reinventing the wheel.
To me, vi is Zen.
To use vi is to practice zen.
Every command is a koan.
Profound to the user,
unintelligible to the uninitiated.
You discover truth every time you use it.