My co-conspirator Bluegill says to nix "versus," as we should not have to choose between the two. Indeed, I'm fortunate have visited both Netherlands and Spain on multiple occasions, and can't really make a pick.
One thing I know for sure is that if Spain wins, Pamplona will experience an even larger party than the one currently being held there. That's because the Fiesta of San Fermin, a.k.a, the Running of the Bulls, is concurrent with the World Cup every fourth year. In 1998, Don Barry and I enjoyed a meal of couscous at a North African restaurant in Pamplona, and remained there in the bar to watch France win the final.
It isn't clear to me how the street party could get any larger, but perhaps where there's an excuse to drink even more, there's a way. At the same time, it would be a mistake to bet against the Dutch when it comes to intensity of the potential celebration (or, for that matter, the drowning of sorrows following a loss). Perhaps the only difference between Pamplona and Amsterdam is that in the former, the bulls shooting past the fallen on Monday morning will be flesh and blood, while further north, they'll be jostling for space tonight in the bars, alongside the other denizens of numerous Star Wars cantina scenes.
Me? I gotta pull for the Netherlands, at least on the pitch itself. Amsterdam is better known for other substances, but there's plenty of good beer there once you get past Heineken -- and some damned fine Spanish restaurants, to boot.