Last week Microsoft snuck in some updates for the SQL Server 2005 product line. Cumulative Update #7 for Service Pack 3 brings you to build # 9.00.4273, while Cumulative Update #17 for Service Pack 2 brings you to 9.00.3356. The only fix for the latter involves MDX queries, so if you aren't using Analysis Services, you aren't getting much -- if you're still on SP2, then perhaps it is time to move to the SP3 line, where this round of cumulative updates bring you no less than 23 fixes.
KB #976951 : Cumulative update package 7 for SQL Server 2005 Service Pack 3
KB #976952 : Cumulative update package 17 for SQL Server 2005 Service Pack 2
If you are using Analysis Services and you are in the SP3 branch (at CU #6), you will want to apply CU #7. For more information see this blog post and KB #978145.
Also, if you have any interest in seeing one last service pack for SQL Server 2005 (SP4), go vote for Steve Jones' Connect item #522122!