I have a large nasty stored procedure in a 13gig database that takes 45 minutes to run when I include the actual execution plan. I save the query plan from SSMS and open in up in SQL Sentry Plan Explorer and I don't see a duration for any of the queries:

I've searched through the entire list of queries and resorted it, the entire column is empty. I know some queries in this particular stored procedure take a long time to run. While the stored procedure is large, it not a stored proc with millions of microsecond queries, and I know for a fact that certain queries take minutes to run.