Yesterday Simon Sabin blogged that the upcoming StreamInsight technology for processing streams of events would only be available in the Data Centre edition of SQL Server 2008 R2.
Turns out that that is actually not the case. In a comment on their blog yesterday the StreamInsight team said:
The details of StreamInsight's alignment with SQL Server SKUs are not fully specified yet, but it will be available with most other SQL Server SKUs as well, not only Data Center.
Reading between the lines I’d say there are some decisions still to be made about what we get StreamInsight with!