I love the regular pho--if you're hungry, get the large (or even the extra large!) The regular pho has beef, tendon, and tripe in it--so if you're not comfortable eating innards, go for one of the custom ones without the tripe/tendon instead--but for the authentic experience, get the whole shebang.
The pho comes with a plate of mung bean sprouts, lime slices, and (maybe if you ask) hot peppers. There are also jars of various Vietnamese sauces at each table--the orangeish red one is really fragrant and spicy, and I recommend dumping it liberally into your soup if you like it hot.
Overall, GREAT restaurant! Apparently they also have desserts, but I've never been hungry enough to try.