It depends on your preferences of course. Flower of Scotland for me is probably number one: it's truly a fighting song, not so old it makes no sense anymore (the Dutch), not just some lame 'our country is the best' thing (USA), just generating a feeling of 'lets go!'. And for singing along, it has a perfect pace, not too fast for example, and indeed, full of emotion
I would honestly not want the Dutch anthem to change, but I definitely only like it because I grew up with it and any replacement would not get remotely close to giving the same feeling....if I wasn't Dutch, I'd find it...meh