need best prime rib in D.C. that is not a chain
Umm...how about The Prime Rib? I argue that it's not really a chain (just a couple of other regional locations), as opposed to Mortons, Ruths Chris, Capital Grille, Smith & Wollensky, et al.
If you're in Fairfax, I highly recommend Vinnie's (http://vinniesfairfax.com/).
Not as expensive as Prime Rib, nor as fancy, Vinnie's has been in Fairfax for a few years now but feels like it has been there forever.
I always get the prime rib, although the other dishes look wonderful. It is wonderfully juicy. But it is rivaled by a great baked potato -- how often have you felt like it was a decision to choose between prime rib or potato?
My carnivore husband and teenage son adore the Calimari -- the dinner size is huge -- they can rarely finish it!
The bread rolls are delicious too, served with real butter.