A good one, if you want to make your application future proof, as MS is working hard to bring stand-alone SQL Server in line with SQL Azure for future releases, and therefore is giving up on some of the concepts available in SQL Server today:
Comparing SQL Server with SQL Azure.
SQL Azure Database is a cloud based relational database service from Microsoft. SQL Azure provides relational database functionality as a utility service. Cloud-based database solutions such as SQL Azure can provide many benefits, including rapid provisioning, cost-effective scalability, high availability, and reduced management overhead. This paper provides an architectural overview of SQL Azure Database, and describes how you can use SQL Azure to augment your existing on-premises data infrastructure or as your complete database solution.
Get ready for the cloud!