Pho Hoa Ky Restaurant has been in business for well over a decade now, and with good reason; or rather, great reasons. It's been voted as the best Vietnamese and pho place by multiple critics, and declared the Best Pho Selection by Best of the Bay 2003. And if you do not like the opinions of food critics, well, I'm a regular guy who eats dines like any average Joe, and I must say, Pho Hoa Ky is really good.
With a ton of different selections available, it'll be hard to pick out just one, two or a few things to try. Allow me to recommend what they're famous for - their pho, made with broth, rice noodles, and your choice of meat (or something else if you're a vegetarian), topped with fresh ingredients such as basil, lime, and bean sprouts.
Your wallet will be as thankful as your mouth. Very, very reasonable prices (less than $6 for some dishes) will leave you satisfied in every way possible. And their service will very good as well. Best Vietnamese restaurant in my opinion. Oh, and if possible, visit them on Sundays, because their best chef only works one day a week.