If you want to invest in something that will last for years, I recommend this Squeem Slimming Shapewear Lace Bodysuit ($89). The fabric is lightweight and breathable while shaping your body, so you don't feel constricted. I also appreciate the lace underwear style of the back — it prevents any unwanted panty lines.
For low-cut dresses, this option is your BFF because it goes into a deep V. It also comes in black and white, so you have plenty of choices. I consider this to be my special-occasion bodysuit that I whip out for big nights.