harrypotterybarn-I wasn't sure if you were aware, but I am a belly dancer and a costume maker by profession...and obviously a nerd as well.
DH and I are in the 501st (Star Wars worldwide costuming charity org) and I do lots of movie replica costumes. My next costumes for myself, are going to be a Slytherin school uniform, AND I am awaiting the movie, because I would like to see if I can replicate the makeup/hair/costume of young Lily, Harry's red haired/green eyed mother from the Snape's Worst Memory scene.
(Although her eyes might be blue in the film due to who they casted as Harry.)
Also-one of my "worlds collide" moments was a few years ago, when I belly danced for Warwick Davis (Professor Flitwick from the Harry Potter films) at the Star Wars C3 convention. It was wonderful-my love for Star Wars, Harry Potter, belly dancing, and costuming all in one awesome moment.
I have lots and lots of theories and things that I have noticed through the books, along with HP discussions that I have had with other HP fans...pretty much dissecting the entire series of books for all of the clues hidden in there.