I love Margaret. I also see it as a timeless classic. I like Maggie and maybe Meg best as nicknames for Margaret. Margot is ok, but not really my style. I also adore Margareta. It was my great-great-great-grandmother's name and I would be more likely to use that form (I also have two Margarets in the family). I love Greta as a nickname, moreso for that than for Margaret, however I like it for both.