I recommend Tan Tan. 1601 Ohlen Rd (I take the Ohlen Rd/Payton Gin exit off 183) (512) 832-9585
Very popular with Vietnamese. Very tasty pho; very flavorful broth. My husband adores the Hue style, which comes with pig knuckles and pig's blood.
Lots of good choices on the menu. Very good meat and noodle dishes.