Gosh what a difficult choice...of all the gowns I just didn't like the ones of Letizia and Máxima, but all the others may well have been my favorite.
I chose the one worn by Mathilde because it was not only perfect for her (and fitted so perfectly), but also because it was perfect for the gothic townhall of Brussels where she got married.
It emphasized her beauty and happiness even more!
But other ones were great as well: Claire's because of the lace, Mary's because it was so romantic, Mette Marit's for its simplicity and unbelievable elegance.