euphonious

euphonious \yoo-FOH-nee-uhs\, adjective:

Pleasing or sweet in sound; smooth-sounding.

She combines alliteration and deft word choices with the grace of an oral storyteller, creating euphonious and precise sentences that are perfect for reading aloud.
-- Amy L. Cohn, "Children's Books", New York Times, March 10, 1991

Einstein originally proposed the more appropriate (but less euphonious) title of "theory of invariants" for his work, but gave up pushing for it when "relativity" caught the public's imagination.
-- James Trefil, "The Most Beautiful Theories Are The Truest", New York Times, October 5, 1986

In the first draft, their names had been alphabetized, but during a speech session Rosenman and Sherwood suddenly perceived the more euphonious sequence of Martin, Barton, and Fish.
-- Carol Gelderman, All the Presidents' Words

Early in life, on the basis of my easy grasp of biological nomenclature and what I consider aesthetic reasons -- all those euphonious names -- I resolved to be a medical doctor.
-- Paul Theroux, Fresh Air Fiend: Travel Writings, 1985-2000

Euphonious comes from Greek euphonos, "sweet-voiced," from eu-, "well" (hence "sweetly") + phonos, from phone, "voice, sound." The noun form is euphony.