10) Diego Costa
Vicente Del Bosque will likely put his faith in the Brazilian to lead the line for Spain, but it isn't yet clear if he can do that particular job to the standard required of the reigning world and European champions.
Can he be the pivot around which the likes of David Silva, Andres Iniesta and Xavi play? The Atletico forward - now destined for Chelsea - is used to a far more direct game at club level and whether he can adapt to the needs of his adopted country will go a long way to deciding how far the holders take the defence of their title.
9) Julian Green
Jurgen Klinsmann attracted much criticism for including Green in his squad while omitting United States icon Landon Donovan. The coach has vehemently denied that it was the promise of a World Cup spot that swayed the Bayern Munich rookie into choosing the US over Germany, but some are having a hard time believing it.
Despite not yet having debuted for his club, the 19-year-old has created a buzz, with Tottenham one of the teams credited with an interest. Green will probably be used as an impact substitute, but with the US facing the might of Germany, Portugal and bogey team Ghana, it is highly likely they will need the teenager's pace, confidence and creativity in the later stages of their matches.
8) Wayne Rooney
Many England fans have lost patience with Rooney, but despite giving him a gentle boot up the backside by shifting him to the left for recent friendlies, Hodgson still needs the 28-year-old.
Rooney failed to score in two previous finals but, unlike the 2006 and 2010 tournaments, the Manchester United striker now claims to be in shape to make an impact. In reality, this is his last chance. Whether he flops or thrills - there is rarely a middle ground for Rooney - it'll probably be the biggest talking point of England's campaign.
7) Ivan Rakitic
The playmaker is the star of a very strong Croatia midfield and the reason Barcelona are so willing to allow Cesc Fabregas to leave the Nou Camp.
The 26-year-old has been one of the Sevilla's most impressive performers on their way to winning the Europa League, and it is that form which has made Barca pounce. Rakitic, Luka Modric and Inter Milan's Mateo Kovacic form a midfield trio which has the potential to make a real impact at the finals, but Rakitic is likely to be the most eye-catching of the three.
6) Robin van Persie
The Holland captain is back in the starring role he loves, playing for a manager who gets him and with a point to prove after a miserable season at club level under David Moyes.
Despite constantly struggling with knocks for the last six years, Van Persie claims he is completely ready for the World Cup, when we could get a glimpse of how Manchester United's attack may be led next season under Louis van Gaal.
The forward, approaching 31, knows this may be his last chance to shine on the biggest stage of all. He will also be acutely aware that his country needs him to perform if they are to get out of desperately difficult group.
5) Sergio Romero
'Tiny', as the 6'3" goalkeeper is known in Argentina, was not able to get in the Monaco side after joining on loan from Sampdoria this season, and it will be fascinating to discover why Alejandro Sabella still rates him so highly.
The Argentina coach clearly has his favourites. Neither of Sabella's likely back-ups, Mariano Andujar and Agustin Orion, are revered in Argentina but both have played under the national team coach previously at club level. Meanwhile, Malaga's rock, Willy Caballero, can't get a look in and Julian Speroni failed to make the 23. It'll be fascinating to see what Romero has got that those two supposedly haven't because I can't fathom it.
Everyone is excited to see Neymar, which is what will make him fascinating to watch. Can he handle the huge burden of expectation?
Probably, yes. The Brazil team do not lean quite so heavily on their number 10 as their supporters do, nor are Selecao as reliant on him as perhaps Argentina are on Messi. Thirty-one goals in 48 international appearances suggest Neymar is at ease in Luis Filipe Scolari's team and all things point to a thrilling tournament for the hosts' brightest star.
3) Edin Dzeko
The striker has never really shed the tag of supporting act at Manchester City, but Dzeko is the star for his country. He combines a spiky character with fierce patriotism and sparks are likely to fly around the Bosnian hit-man.
Bosnia may be the only debutant participant in Brazil but they are many people's dark horses, with the quarter-finals a realistic target, thanks largely to Dzeko's form. The tall frontman scored ten in ten in qualifying and comes into the tournament in good nick, having scored 16 goals in only 23 starts for the Premier League champions. With Miralem Pjanic pulling the strings behind him, Dzeko is a good outside bet for the Golden Boot.
2) Arturo Vidal
The Juventus star is arguably the most complete midfielder in the game and key to the hopes of a Chile side who could be one of the most exciting sides at the finals.
Vidal is a force both defensively and in attack, with the 27-year-old netting 18 times for the Serie A champions this season. At international level, half of his eight goals in four-and-a-half years in the Chile midfield have come in the last 12 months, with Vidal benefiting from the ability of Chile's primary attackers, Alexis Sanchez and Eduardo Vargas, to pull defences almost wherever they wish.
New United boss Van Gaal has confessed his admiration for Vidal and the Dutchman must find a way to stop the midfield dynamo when Netherlands meet Chile in what may be a Group B qualification decider on June 23.
1) Cristiano Ronaldo
In Ronaldo's mind, this is his tournament. The Ballon d'Or winner and European champion dragged Portugal to Brazil, where he will be determined to outshine Messi, despite the handicap of playing for an inferior side.
The 29-year-old has peaked in time for these finals. The fact he will have to shine from the start if Portugal are to go far enough to give him the platform to win the Golden Ball he craves makes him even more dangerous.
Ian Watson - follow him on Twitter
Seeing Ronaldo posturing and attitudinizing in that picture after scoring the fourth goal from the penalty spot in the Champions League, and hearing he actually knew where to go stand for the benefits of the camera, I genuinely believe should he help win the World Cup for Portugal you would be able to power a small country, like Monaco, from his ego alone.- hump3.