Q: Exchange Server 2010 support how many databases per Standard vs Enterprise? How does DAG affect this?
ANSWER: Standard supports a maximum of 5 active databases (DAG capable) and 257 passive databases. Enterprise supports a maximum of 100 active databases (DAG capable) and 257 passive databases.
http://www.amazon.com/Microsoft-Exchange-Server-2010-Practices/dp/0735627193