Go get all the goodies at http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/servicepacks/sp2.mspx, including an updated books online (BOL) and feature pack (lots of good stuff, including JDBC drivers, MSXML 6.0, command-line tools, SQL Server 2005 Compact Edition, and so much more).
And as a teaser, here's an excerpt from the "What's new" page:
Added new functionality in the SQL Server 2005 Enterprise Edition to provide another storage format that can be used to minimize the disk space that is needed to store existing decimal and numeric data types. No application changes are required to use its benefits. This new storage format, known as vardecimal storage format, stores decimal and numeric data as variable length columns and can be enabled or disabled at a table level on new or existing tables. If you have declared a decimal or numeric column with high precision but most values in the column do not require many digits of precision, you can potentially save a large amount of the disk space that is needed to store the table. A new stored procedure is provided to estimate the reduction in average row size with the new storage format. For more information, see Storing Decimal Data as Variable Length.