I'm seeing some weird problems with border-radius when used with vertical-align:middle in IE9 that no other browser experiences. In IE8 the problem is gone (because border-radius is not rendered). Also border-radius of 3px is not visible on larger objects when it's visible in every other browser. When you bump it to 3.6px, suddenly it's visible.
Wow. So now we're going to need IE9 CSS hacks. Unbelievable.