I use this chart to show the most active users (save the report as "Chart: xxx"):
Select Top 1000000 htblusers.name,
Count(tblLoginLog.LogID) As logins
From tblLoginLog
Inner Join htblusers On tblLoginLog.UserName = Concat(htblusers.userdomain,
'\', htblusers.username)
Group By htblusers.name
Order By logins Desc