Joining Table On On Last Entered Record

Dear All,

What's the most efficient way of joining a 1 to many relation, where a record in table A will have multiple records in table B.

I'd like to select every record in table A but only joining the last relevant record from table B. So:

Table A:

A1 Prj1
A2 Prj2

Table B:

B1 A1 23/12/2005
B2 A1 26/12/2005
B3 A1 2/1/2007
B4 A2 25/12/2006
B5 A2 1/1/2007

So I'd like to list using the most efficient way this:

A1 Prj1 B3 2/1/2007
A2 Prj2 B5 1/1/2007

I'm assuming this is NOT the most efficient way:

select A, (select top 1 date from B orderBy ...)

Any suggestions?