Hi dlamarche,

Try in C1 and copied down,

=IF(COUNTIF($A$1:$A$7,B1)=0,B1,0)
In D1 and copied down,

=IF(ROW()-0>COUNTIF($C$1:$C$7, "<>0"), "", INDEX($C$1:$C$7, SMALL(IF($C$1:$C$7<>0, ROW($C$1:$C$7)), ROW()-0)))
confirm with Ctrl+Shift+Enter

HTH

Kris