The decision to nurse or not is a no-brainer. If you want the healthiest, happiest kids you'll use what nature gave you to nourish them. Expecting twins? Perfect, because you have two (breasts)!
Think of the difference when, in the wee hours, the babes are hungry. Keep in mind that you are exhausted, because sorry, but sleep is just something you will get little of for a while. Would you rather 1) have to get up, leave the cryers, prepare factory produced formula, heat it in bottles that you have had to wash and sterilize, return to the cryers, and hold the bottles so the babies can ingest the chemically enhanced cow or soy milk OR 2) Arrange the pillows, get one latched on, the other latched, and relax while they suckle. That's just the difference for you. There is no way a production facility can re-create the miracle your mammary glands make. Even the formula companies admit that breastmilk superior.
I know I can wax cynical, but really, giant food production companies do not care about your babies' health. They care about profits.
I, and many others, exclusively nursed twins. In the early days, I tandem nursed 3 because my next oldest was only 2 years old. The twins weaned themselves this year, the week after their 4th birthday. We've enjoyed excellent health and unbreakable bonding, I got more rest than I would have otherwise, and postpartum weight loss was a non-issue.
For more information, get in touch with your local La Leche League. They are wonderful and helpful.