There is.

SET ANSI_NULLS OFF

the reason it is not recommended is because as the name of the variable suggests, you are turning off an ANSI standard which can lead to compatibility issues should that code ever be moved, etc.

but if you cant live without it, there you go.

No warranties implied blah blah blah.

-d

Edit as per BOL:

This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature.