Edition Differences in SQL 2008

Based on the current whitepaper from Microsoft it is extremely important to pay attention to which version of SQL 2008 you pick. A lot of features are once again Enterprise only, to include multiple instances, which previously was available in SQL 2005 Standard. I am not sure why this would be moved up to Enterprise Edition, but will be asking some experts and making a post on the 2008 Forums to find out more information.