How Can I Log and Find the Most Expensive Queries?

RPC:Completed
SP:Completed
SP:StmtCompleted
SQL:BatchCompleted
SQL:StmtCompleted

SELECT * INTO TraceTable
FROM ::fn_trace_gettable('C:location of your trace output.trc', default)

SELECT COUNT(*) AS TotalExecutions,
    EventClass, CAST(TextData as nvarchar(2000))
 ,SUM(Duration) AS DurationTotal
 ,SUM(CPU) AS CPUTotal
 ,SUM(Reads) AS ReadsTotal
 ,SUM(Writes) AS WritesTotal
FROM TraceTable
GROUP BY EventClass, CAST(TextData as nvarchar(2000))
ORDER BY ReadsTotal DESC