I used to be able to do the following in SQL 2000 without any problems:
Update <table1>
Set <field1> = (Select <field2> From <table2> t2 Where t2.<PKField> = <FKField>
Now in SQL 2005 when I check syntax the query gets rewritten automatically to:
Update <table1>
Set <field1> =
(Select <field2> From <table2> AS t2 Where <PKField> = <FKField>