While I love Vietnam, sometimes the wait gets to me, and we head over to Nam Phuong on Washington Avenue (website attached). Not as pretty as Vietnam, but while usually crowded not a huge wait for a table, and the food is delicious.
Great suggestions. Som Sak is very popular - with good reason - make a reservation if you are going at a busy time. Vietnam is always good. Siri's is more fusion - kind of a continental menu, for the most part.