I am interested in a list, as exhaustive as possible, of hotels having
the following criteria.  Musts include fireplace in room and
comfortable sofa or chair and lamp for reading by the fire on a cold
winter night.  They should have several, but not necessarily all, of
these plusses too: king-sized bed, whirlpool in room, breakfast on
premises, nice view (cityscape or mountains or quaint town, as
examples), short walk from restaurants/shopping.  The regions I'm
interested in are Baltimore/Washington/Annapolis/Fairfax metro area
and Philadelphia/Wilmington metro area (say, within 50 miles or so of
mentioned cities).

I cannot provide an exhaustive list, but I can make one recommendation for you.

My husband and I spent a weekend in a Comfort Suites hotel in Ocean
City, MD.  We liked it because it was close enough to home to get away
for a weekend without spending all our time driving to/from our
destination.

The hotel has suites, at a very reasonable price, that have a very
large jacuzzi for two -- perfect for relaxing together.  There's lots
of room around the tub if you want to get a $5 bag of tealights from
Walmart and surround yourself with atmospheric lighting.  Adjacent to
the tub, there is a fireplace with glass surrounding it on three
sides, including the side that faces the bed.  The bed is king-sized
and comfortable.  A nice, continental (plus) breakfast is served in
the lobby -- self-service allows you to load up your plate and bring
it back to the room if you want.

Hope you have a great time -- wherever you may land!