Spain may be perennial underachievers in the World Cup, but at the club level the nation boasts some of the most successful and entertaining teams in the world.

The top Spanish league is one of the best in the world, and FC Barcelona is currently the cream of the crop. The reigning champs of La Liga and the UEFA Champions League have managed to overshadow rival Real Madrid with relative ease for two straight seasons. They have comfortably held off the challenge from an ageing ‘Galactico’ Madrid side to win back-to-back titles, and change isn’t likely.

Barcelona has a squad of players that other managers envy. The defence is superbly marshaled by Captain Carlos Puyol. His composure and tough tackling provide the foundation for the dazzling attacking displays we have come to expect from Frank Rijkaard's side. This defence should prove an even tougher nut to crack with the addition of veteran French defender Lilian Thuram, who arrives from crisis-stricken Italian club Juventus, in a $24.62 million double transfer that also includes Italian international defender Gianluca Zambrotta.

Barca have also boosted their attacking options with the addition of striker/midfielder Eduir Gudjonson for $11 million from European rival Chelsea as a replacement for outgoing Swedish veteran Henrik Larsson. Gudjonson's arrival will boost competition for scarce playing time on a side that already boasts the incredible talents of Messi, Deco, Guily, Eto’o and current world footballer of the year, Ronaldinho.

Keeping all these stars happy may be the biggest challenge for manager Frank Rijkaard and already there are signs of unrest, with striker Samuel Eto’o going AWOL after being replaced by Gudjonson at halftime of a recent match against Espanyol.

Real Madrid, Barca’s closest challenger, will be hoping that these early signs of dissent will help them close the gap on their great rivals in the race to win the league this season. After three trophy-less seasons, numerous managerial changes and a change in transfer policy, supporters of the most famous and decorated club in Europe will be hoping Fabio Capello's second year in charge will bring with it a new era of stability and success.

It is well documented that Madrid supporters will not tolerate anything less than winning either La Liga or the Champions League in any given season, so to go three years without a trophy in either while watching their rivals win both would be tragic.

Madrid may be looking at a rebuilding phase though. The retirement of former world player of the year Zinedine Zidane will hit the club hard. Moreover, superstars David Beckham and Ronaldo may not be part of Capello’s vision for the future, which includes taking advantage of the misfortunes of his former club Juventus. The arrival of Italian World Cup winning captain Fabio Cannavaro, from the much-maligned Italian club, should shore up a defence that has been far from water tight in recent seasons. The additional signing of Brazilian enforcer Emerson from Juventus and midfield dynamo Mahamadou Diarra from Lyon will add some much needed bite to the club’s midfield, dubbed the ‘Warriors’ by Capello.

The summer capture of Dutch international Ruud Van Nistelrooy from Manchester United though will give the Madrid faithful the most hope that they can break Barcelona’s recent dominance. Van Nistelrooy, 30, was a prolific goal scorer both domestically and in European competition for Manchester Utd. and Real will be hoping he can reproduce the form that bagged him 150 goals during his time in England.

Along with Madrid, Valencia appear to have the best chance of challenging for the title this year as they have also strengthened in their quest to improve upon their 3rd place finish last season

The arrivals of Spanish international left back Asier Del Horno from Chelsea and striker Fernando Morientes (disappointing with Liverpool, have given supporters hope that they can repeat their title successes of 2002 and 2004. However, the club’s unsuccessful summer-long pursuit of star Cristiano Ronaldo has been fuitless, even though the club stated that Manchester United could ‘name their price’ for the Portoguese star. Unfortunately for Valencia, the English club’s insistence that Ronaldo won’t be transferred could spell the end of Valencia’s bid to dethrone Barcelona.

The race for fourth and the final coveted berth in the Champions League would seem to be between Athletico Madrid, UEFA Cup champions Sevilla and 2006 Champions League semi-finalists Villareal.

Athletico have appointed Mexican coach Javier Aguirre after being impressed with how he led Osasuna to the Champions League qualifiers and his first action as boss was to secure the services of in-demand Argentine teenage forward Sergio Aguero.