jaz my 2 cents:
probably because a girl is more focused on fashion (READ: shoes, make up, bags, dresses, jeans, blouses and the like)
and guys are focused on toys/gadgets (READ: ht, cars, mobile phones and the like)
but for me (i'm a girl btw
) i collect them mainly because i simply love revisiting movies that i enjoyed....so my humble vcd collection is now being replaced by dvds