The slide's title should tell the slide's story

Don't be shy about using the title to direct the audience toward the overarching message of the slide.  Every slide should have one overarching message and the title should relate that message.  Remember presentations are not easy for the audience to understand so you need to guide them to the points you want them to comprehend.  No need to be subtle.

The slide below shows trial accrual for six years.  I could have used a bland title like, "Accrual to trials 2006-2011."  However I really want the audience to focus on what happened in 2011 and want to pass a message about why there was a drop in accrual. 

If this were a journal article I might have used the more objective title.  In a journal article you'll have a spacious caption to explain what you want the audience to get out of the figure.  The reader has more time to digest the data.