The last one, absolutely the last one. If you're almost hourglass-y, it will totally nip you in at the waist with that wide, fitted waistband. The deep V neckline will flatter a larger chest, and the skirts with petticoats underneath will provide volume to balance you out and that much fabric sweeping around you will be spectacular. Avoid #3 if you are larger of boob, since that neckline will give you a monoboob of epic proportion. I think #2 is a non-starter; if I'm being brutally honest I think it's kind of ugly. Also, without a degree in engineering to fabricate some kind of scaffolding in there, I think you're going to run into boob-age issues. #1 is cute enough, but it seems a bit blah really.
Which ever you go for, the key to a showstopping appearance is to make sure the thing fits you like a glove and is perfectly finished A quality fabric will really pay off, especially as the majority of store-bought gowns don't exactly employ the highest quality of component. And wear it with your head held high knowing that you look bloody amazing!