Ugly Betty (super easy- I'd just have to put on a whole slew of different, somewhat clashing items, and I already have a pair of red glasses)
Or June Cleaver type. I'm not willing to wear a wig to fully complete the look, so I suppose I'd be simply a 1950s housewife. I know the dollar store carries child tea sets, so I could glue a set to a tray and carry it around with me.
I'm also considering a magic 8 ball (dress in all black, and attach a white 8 to my middle) or a sailor. It's a good thing I still have a couple of days to decide!