You can install SSRS on Vista if you configure IIS7 with legacy IIS6 support:
http://www.kodyaz.com/articles/iis7-installation-for-reporting-services.aspx

The build order is key - I installed SP2 on SQL Express before installing the full SQL Server 2005 Dev edition. SP2 uninstall requires removing and reinstalling SQL Server. Make sure to configure IIS, install VS2005, SQL 2005, then install SP2.