Michael19 said: "If I had my choice, I would love Donna Murphy or Christine Ebersole—I think either would be wonderful. Donna would be my first choice though."
Either one would be great at the "low comedy" the part requires, but it's really a mezzo-belter's role, as are all of Merman's signature roles.
Ethel Merman, Benay Venuta (Merman's perennial understudy), Elaine Stritch (Merman's standby two decades before smoking and drinking destroyed her voice (granted, in an interesting, "character" way)), Tyne Daly (no Merman vocally, but she sings in the same style), Karen Morrow (the last Sally Adams I saw). These are the sort of "belting broads" who have played the role and are right for it.