From the annoucement:

We focused our work around three themes: everyday browsing (the things that real people do all the time), safety (the term most people use for what we’ve called ‘trustworthy’ in previous posts), and the platform (the focus of Beta 1, how developers around the world will build the next billion web pages and the next waves of great services).

Hopefully IE8 will fix some quirks from IE7 and us (web developers) can have a decent time. Also i would love to see Microsoft making the minimal browser requirement on their sites to be ie7 so we can dump that nightmare called IE6