As this article's figure 4 says, SQL Server 2005 + can return you a list of missing indexes. It stores 2 important info about missing indexes:
[EqualityUsage],[InequalityUsage]
If I have a missing index where:
[EqualityUsage]='col1',[InequalityUsage]='col2'
Should I create an index with Indexed Key Columns:
'col1,col2'
or
'col2,col1'
?