If you have anything to do with Reporting Services in the near future these two links are must read for you.

SQL Server 2005 Reporting Services (SSRS)
Among all new features, the following ones are shining brightly for me.

Custom Report Items
SQL Server 2005 Reporting Services enables Independent Software Vendors (ISVs) and developers to extend report processing through the creation of custom report items.

Report Builder Client
The Report Builder client is a ClickOnce WinForms application launched from the Report Server. The Report Builder user interface is built on top of familiar Microsoft Office paradigms such as Excel and PowerPoint.

Report Builder Model Designer
When an end user builds a report with Report Builder, they use a business model representation of the underlying database schema. Providing reporting access to this business model precludes the end user from having to understand, for example, connection strings or how to write SQL or MDX. While models that provide access to SQL Server Analysis Services are automatically generated on the Report Server, the Report Builder Model Designer can be used to generate or modify the models that are built on top of SQL Server relational databases.

SQL Server 2005 Features Comparison
You will find out that Reporting Service is available in all editions of SQL 2005. That’s cool!!!