Ohh Sheana, a flap would be a stunning addition to your fabulous collection!
I adore flaps... hmm, I would say it's a tie between 3 and 1 (but only if 3 is the off white soft caviar flap with the MM lock/chain - I have and absolutely LOVE that bag)! I think the Jumbo is a gorgeous bag, but since you like to dress up when you go out, I think a medium flap would be better.
IMO, the medium classic flap is a great size for daytime essentials, and obviously great for night... if you want something a little different, the black caviar flap with the bijoux chains is really pretty, or white if you can find it.
Of course, you can't go wrong with the classic flap in black w/ silver hardware either! Haha... I'm not sure I helped at all, but I would say get either the following:
a. an off white soft caviar flap w/ MM lock and chains or
b. a black caviar medium flap w/ the bijoux chain or with the regular chain! Can't wait to see what you get!!