I got the sense from MS employees at PDC that the browser situation would be much improved within 6 months.
I don't especially want it to fail, as the market is ripe for competition and it will keep pushing Apple and Google forward, but as an app developer that really just wants to stay on the 'pure web' now, it's an unwelcome extra column in the already big matrix of things to have to specially support...
[1] http://www.silverlightshow.net/news/Silverlight-and-PDC.aspx
ACID3 is largely DOM and Javascript.Here's a good article to read about the ACID3 test, from a name you probably know: http://meyerweb.com/eric/thoughts/2008/03/27/acid-redux/