The princess has a dazzling collection of designer gowns, several of which will go down in history. Credit: Getty ImagesThe GistKate’s most expensive dresses range from $4,428 to a staggering $434,000.Alexander McQueen and Jenny Packham are her go-tos for formalwear.Like Princess Diana, Kate regularly revisits her designer gowns, sometimes decades later.From Princess Diana’s extravagant evening gowns to Kate Middleton’s $434,000 Alexander McQuee…