Tom Wood: He may have missed out on the captaincy but Wood remains a talismanic figure for England. The Northampton back row is a decent lineout option and is dogged at the breakdown, while his pace can cause problems in the midfield channels. Wood is a versatile, combative figure and not afraid to get stuck in, and has developed a good understanding with Chris Robshaw. Should England's backline continue to falter, he will again be required to make some hard yards.
Wesley Fofana: One of those magical players who just oozes class and always seems to have plenty of time on the ball - a rare gift. Incredibly Fofana came to rugby late in life and by his own admission only started to focus properly on rugby at the age of 22. Now 26, he is one of Philippe Saint Andre's key men and while France may be struggling, Fofana may just be the man to get them back to their best.
Jamie Heaslip: With Sean O'Brien sidelined through injury, his Leinster teammate needs to make a bigger impression with ball in hand. Heaslip is one of the most divisive figures in Irish rugby, but the No 8 showed what an influential and powerful player he can be against New Zealand last November. Chris Henry - O'Brien's likely replacement at openside - is a menace at the breakdown, which should free up Heaslip to make more carries.
Sergio Parisse: if anyone can inspire Italy's young troops it is Parisse. Despite being on the end of more losses than wins in his international career, Parisse always stands out with his hard work and exceptional skills. He may have lost his crown as the world's best No.8 to Kieran Read, but Parisse is still up there as a genuine world-class player.
Greig Laidlaw: The latest in a fine tradition of Scottish scrum-halves that includes his uncle Roy, part of the 1984 Grand Slam-winning team. The Edinburgh skipper was finally given an extended run in the No 9 shirt last year after spending 2012 as Scotland's preferred stand-off. His excellent kicking game is complemented by impressive decision-making and leadership, evident in the way he marshals the pack and knows the right time to move the ball wide. Laidlaw also shoulders place-kicking duties and much depends on him if Scotland are to improve on last year's third place Six Nations finish.
Leigh Halfpenny:The 2013 Lions player of the series needs to be at his very best if Wales want to get that unprecedented third title in a row. A world-class player who has the ability to produce the goods when the pressure is on. He will play a key role in their success.