as someone who deals with the front end for a company whose business is a web app, no support for ie6 (with patch files, conditionals, whatever) really is a deal breaker. the sad fact is 15% of our customers still use ie6.

draw your own conclusions, but those customers generate significantly higher revenues per customer than those who use modern/semi-recent browsers.

960s is great.

I like the idea of a real baseline grid, but...

"Safari 3, Google Chrome, Firefox 3, Opera 9 and Internet Explorer 8 all work correctly with some minor differences."

Seems like cross-browser compatibility (including Firefox 2, IE7, and heck if you're making a framework, IE6) would be at the top of the list of your priorities when creating something like this, though ;-).