55 gal is a great size for a few angels.. i've got 5 angels with some guppies and mollies in a 45 gal corner tank. the small fish are just there to keep the angels from fussing with each other.
At 4 foot long a 50 or 55 gallon tank can have a lot of uses as a single pair breeder...grow out tank...or even temporary housing during tank set up. Although what most of us on MFK keep require large tanks you don't want to loose sight of the usefulness of the tryed and true double nickels...