Hmm, with your responses I wouldn't be to alarmed about enabling lock pages in memory then, but it is still good practice to have it enabled.
You may want to read up on these articles: http://blogs.msdn.com/psssql/archive/2007/05/31/the-sql-server-working-set-message.aspx
http://blogs.technet.com/askperf/archive/2007/05/18/sql-and-the-working-set.aspx