Microsoft has released Microsoft SQL Server 2008 R2 RTM Express

The Microsoft® SQL Server® 2008 R2 RTM - Express is a powerful and reliable data management system that delivers a rich set of features, data protection, and performance for embedded applications, lightweight Web Sites and applications,, and local data stores. Designed for easy deployment and rapid prototyping, this download includes support for Sysprep, Microsoft's System Preparation Utility for Microsoft Windows operating system deployment.

SQL Server Express with Management Tools is an easy-to-use version of the SQL Server® Express data platform that includes the graphical management tool SQL Server Management Studio (SMSS) Express

Microsoft SQL Server 2008 R2 RTM Express