There’s a bunch of information about how IE10 will be handling HTML5, but the bit that sticks out to me is that IE will no longer support Conditional Comments as of version 10.
Conditional Comments have been a controversial issue since becoming widely adopted as a method of avoiding CSS hacks. I, for one, have stood behind Conditional Comments fot some time and use them in sites to this day. As with all things though, Conditional Comments have been abused over time, which likely put a bad taste in the mouths of many developers.
I think that the IE team deciding to drop Conditional Comments speaks to the fact that they’re doing all they can to adhere and become more relevant given their lifespan thus far.
It’s been a long time since I’ve had to write maybe a CSS declaration or two targeted only at Internet Explorer, but I’m hoping by the time IE10 comes out, that average drops even further.