Thanks for the awesome post Andy. About time we look at things from this new perspective, and the more designers follow this method of development, the more quickly the non-techie world would notice the “consistently appearing differences” across different browsers thus getting rid of – “but so many sites look the same at work and at home… why not my own?”. It is recommended to educate the clients or at least notify them about the differences, and i loved the way you put it on your site too –

we’ll ask you whether you want us to spend our time and your money on workarounds for outdated web browsers such as Internet Explorer 6 or on features that will benefit your business and improve the success of your site