So will we see a two-legged El Clasico and a Bundesliga derby, or will it be Spain against Germany in both semis?
I've just driven through the Alps from Turin (where I witnessed Bayern Munich dismantle Juventus) to Nyon in Switzerland by the shores of Lake Geneva (where the semi-final draw will take place on Friday morning at UEFA's headquarters).
Let's start with Jupp Heynckes' all-conquering side. Newly-crowned German champions, Bayern Munich are on an amazing run of success: 11 consecutive away victories and 16 wins from their last 17 games in all competitions.
Goals from Mario Mandukić and sub Claudio Pizarro gave Bayern victory at the Juventus Stadium and it's difficult to look past them as potential Champions League winners. Even with Toni Kroos injured, the German side still have an abundance of match winners - Thomas Muller, Franck Ribery, Arjen Robben and Bastian Schweinsteiger.
After the heartbreak of losing to Chelsea on penalties at their own home ground last year, Bayern's fans are convinced it's their destiny to win this season's final in London - at Wembley.
That's easy to understand, but in their way are three absolutely top sides.
Borussia Dortmund were perhaps the most impressive team of all in the group stages, emerging unbeaten at the top of the 'group of champions' with victories over Real Madrid, Manchester City and Ajax Amsterdam.
The 1997 champions under their charismatic coach Jürgen Klopp have been a revelation. An extraordinary fightback against Malaga proved they have a bit of steel as well. In Robert Lewandowski, Mario Götze and Marco Reus they have players who are showing they are more than comfortable at this level.
Never ever write off Barcelona!
The four-times champions have had scares in the knockout rounds against both AC Milan and Paris Saint-Germain, but they have still found a way through to a record sixth consecutive semi-final.
Lionel Messi and co will remain the team to beat - even if they haven't quite managed to recapture their magical form of previous seasons. Twice before they've reached the final when it's been at Wembley and twice they have won - in European terms they almost see it like a second home.
Last but not least Real Madrid. They have the X-Factor with José Mourinho and Cristiano Ronaldo and like Barça they are finding ways to win when not at their best. Victory at Old Trafford in the last 16 suggests this is a team capable of finally going all the way.
They lost on penalties at this stage last season to Bayern Munich and went out to Barcelona in the semis two years ago. Logic would dictate they'd therefore prefer to face Dortmund - but only a late equaliser in Madrid prevented them from losing back-to-back games against the Germans in the group.
For Real (like Bayern) the Champions League is becoming something of a Holy Grail. Their last success was in 2002 and they would love to repeat that triumph soon.
But one thing is clear: there are four top-quality teams in the semi-finals, any two would be worthy finalists so choosing a winner is almost impossible - that's why it's such a fascinating prospect!