Hi Carly---
While I'm not a real aficionado of Vietnamese cuisine, I absolutely love the marriage of Asian & French qualities, along with the addition of fresh vegetables & herbs. It's also a very healthy cuisine.
You will not go wrong if you stick with these Viet staples:
Bun Bo--thin rice noodles topped with marinated & sauteed onions and satay beef, shredded raw carrots, cucumber, bean sprouts and cilantro, and dressed with a slightly spicy vinegar sauce and chopped peanuts. Hot & cold together, magnificent.
Lemon Grass Chicken--boneless breast or thigh, wokked with onion with lemon grass (a phenomenal aromatic herb), served over lettuce leaves with steamed rice.
Vietnamese Iced Coffee--in a tall glass filled with ice, sweetened condensed milk mixed with Viet espresso that traditionally drips down through a metal filter. Believe me, a perfect complement to the food above.