SQL Server - where is "sys.functions"?

Another way to list functions is to make use of INFORMATION_SCHEMA views.

SELECT * FROM INFORMATION_SCHEMA.ROUTINES WHERE ROUTINE_TYPE = 'FUNCTION'

According to the Microsoft web site "Information schema views provide an internal, system table-independent view of the SQL Server metadata. Information schema views enable applications to work correctly although significant changes have been made to the underlying system tables". In other words, the underlying System tables may change as SQL gets upgraded, but the views should still remain the same.

I find UDFs are very handy and I use them all the time.

I'm not sure what Microsoft's rationale is for not including a sys.functions equivalent in SQL Server 2005 (or SQL Server 2008, as far as I can tell), but it's easy enough to roll your own:

CREATE VIEW my_sys_functions_equivalent
AS
SELECT *
FROM sys.objects
WHERE type IN ('FN', 'IF', 'TF')  -- scalar, inline table-valued, table-valued