"That is, unless you want an inconsistent experience for your users."
I'm not so sure why people fight so hard for an IDENTICAL experience between browsers. People running IE6 probably won't even notice your square corners. This is why I keep proposing serving a mobile version to IE6 users. The next time something is off by one row of pixels in IE6, completely ignore it. Chances are, IE6 users will too.
It's not like the IE6 people are also going to be running Firefox to do a side-by-side comparison of how your page renders. Unless they have some new and fascinating psychological abnormality, of course.
I'm not so sure why people fight so hard for an IDENTICAL experience between browsers. People running IE6 probably won't even notice your square corners. This is why I keep proposing serving a mobile version to IE6 users. The next time something is off by one row of pixels in IE6, completely ignore it. Chances are, IE6 users will too.