The 28-year-old Munster man kicked 20 successful place-kicks throughout the Championship - 14 penalties and 6 conversions - as well as two drop goals against England, for a five-game haul of 60 points.
Wales' Stephen Jones, O'Gara's closest rival and perhaps biggest challenger for a Lions' Test team spot this June, depending on the fitness of England's Jonny Wilkinson - had 22 successes for a 57-point return.
O'Gara admitted in the aftermath of the 32-20 loss to the Dragons: "The charge-down try was a killer. I didn't see him (Gethin Jenkins) and that made it 10-3 - after we had started the game well.
"We were chasing them from then on, but every time we got into a good position we gave away a penalty. We were penalised for indiscretions that baffled us a bit - but the better team won on the day."
Ireland's David Humphreys - who kicked three conversions from three in the tournament, two against the Welsh - had a 100% return for the 5 minutes he saw at Murrayfield and Cardiff's half-hour effort.
2005 Six Nations: Top Points Scorers:
Others: Denis Hickie, Brian O'Driscoll, Geordan Murphy (Ireland) all 10, David Humphreys (Ireland) 6
Kickers' Top Place-kick Percentages:
Andy Goode (England) 1/1, David Humphreys (Ireland) 3/3, both 100%; Gert Peens (Italy) 4/5, 80%; Dimitri Yachvili (France) 18/24, Frederic Michalak (France) 3/4, Stephen Jones (Wales) 22/29, all 75%; Ronan O'Gara (Ireland) 20/27, 74%; Chris Paterson (Scotland) 16/23, 69%
Top Try Scorers:
Mark Cueto (England) 4, Kevin Morgan (Wales), Jamie Noon (England), Martyn Williams (Wales), Shane Williams (Wales) all 3, Andy Craig (Scotland), Christophe Dominici (France), Denis Hickie, Brian O'Driscoll, Geordan Murphy (Ireland), Josh Lewsey (England), Rhys Williams (Wales) all 2
Others: Gavin Duffy, Marcus Horan, Paul O'Connell, Malcolm O'Kelly (Ireland) all 1