Limiting report data to one line per account

Hi,

I am trying to create an activity history report that shows the last created date for each account.

I have created a report that shows

Account ID

Account Name

Priority

Activity Created Date

Field showing NOW()

Calculated field showing the # of days from the created date.

I would like to report to show only the newest (lowest) # of days for each account.  I only need one line / account.  I have tried, min, max and rank and neither will give me what I need.  Any suggestions?

Stu