Today, Chris Wilson spilled the beans I've been wanting to spill for awhile -- The majority of the features (bug fixes) that will effect web developers are in Beta 2, not Beta 1 of IE. Here is a quick list of things that are addressed -- see Chris's post to understand the rationale -- The work the IE team is doing is pretty amazing, and just the start of a dedicated effort to provide our Web developers with the best possible experience across the board -- whether it is with tools and platforms, or browsers.
In IE7, we will fix as many of the worst bugs that web developers hit as we can, and we will add the critical most-requested features from the standards as well. Though you won’t see (most of) these until Beta 2, we have already fixed the following bugs from PositionIsEverything and Quirksmode:
In addition we’ve added support for the following