Best: Runners-up (1974)
Star man: Diego Costa
Overview: Have let their chances of winning the Primera Division slip lately, but they are still having a superb year thanks to the 22 goals of Diego Costa. A 5-1 aggregate win over AC Milan in the last 16 will have done their confidence no harm.
Best: Winners (1992, 2006, 2009, 2011)
Star man: Lionel Messi
Overview: Also likely to lose out to Real Madrid for the La Liga title following a recent dip in form. Kept their European dream alive with relatively straightforward 4-1 win over Manchester City in the previous round.
Best: Winners (1974, 1975, 1976, 2001, 2013)
Star man: Franck Ribery
Overview: Pep Guardiola is hoping to join an exclusive club of coaches who have won the Champions League with two different clubs. Bayern, unbeaten in the Bundesliga, wasted little effort getting past Arsenal in the second round.
Best: Winners (1997)
Star man: Robert Lewandowski
Overview: Defeated by Bayern in last year's final. Some 23 points behind their rivals in the Bundesliga and went down to a disappointing home defeat to Zenit St Petersburg in the second leg of their last-16 tie.
Best: Winners (2012)
Star man: Eden Hazard
Overview: Chelsea surrendered the initiative to Manchester City in the Premier League title race last weekend when they lost to Aston Villa, but few would bet against Jose Mourinho winning a third Champions League trophy after their ruthless display against Galatasaray in the last round.
Best: Winners (1968, 1999, 2008)
Star man: Robin van Persie
Overview: David Moyes has endured a horrid debut season domestically, but his team gave United fans a night to remember on Wednesday when they overturned a two-goal deficit to progress at the expense of Olympiacos.
Best: Semi-finalists (1995)
Star man: Zlatan Ibrahimovic
Overview: Deprived of a place in the World Cup, Ibrahimovic will be looking to prove to the world that he is just as good as he thinks he is. PSG's expensively-assembled squad hammered Bayer Leverkusen 6-1 on aggregate in previous round.
Best: Winners (1956, 1957, 1958, 1959, 1960, 1966, 1998, 2000, 2002)
Star man: Cristiano Ronaldo
Overview: After a 12-year wait, this could finally be the season when Real Madrid finally achieve la decima (the 10th European Cup). Ronaldo is two goals shy of breaking Lionel Messi's record of 14 in one Champions League campaign following his four-goal haul in the 9-2 aggregate win over Schalke.