I rather like Ellen Taaffe Zwilich's post-modern, neo-romanticism ;D and rate her fairly high amongst contemporary American composers. She is, in my opinion, well worthy of investigation. Unfortunately, although a good deal of her music has been recorded, a number of the releases were on the Koch label and they may no longer be always easy to find.
ELLEN TAAFFE ZWILICH: A CATALOGUE OF THE ORCHESTRAL AND CHORAL MUSIC
1973: "Symposium" for orchestra: 12 minutes
1982: "Passages" for soprano and orchestra: 25 minutes + (Aca cd)
1982-83:Symphony No.1 (Three Movements for Orchestra): 17 minutes + (New World cd)
1983: Prologue and Variations for string orchestra: 12 minutes + (New World and Albany cds)
1984: "Celebration" for orchestra: 8 minutes + (New World cd)
1985: Concerto Grosso 1985 for small orchestra: 13 minutes + (Koch and New World cds)
Symphony No.2 "Cello Symphony": 25 minutes + (First Edition cd)
1986: Piano Concerto: 25 minutes + (Koch cd)
"Images" for Two Pianos and Orchestra: 18 minutes + (Naxos cd)
1987: Ballet "Tanzspiel": 28 minutes
1988: Concerto for Tenor Trombone and Orchestra: 20 minutes + (BIS cd)
"Symbolon" for orchestra: 16 minutes + (New World cd)
"Ceremonies" for concert band: 18 minutes
1989: Concerto for Bass Trombone, strings, timpani and cymbals: 19 minutes + (Koch cd)
Flute Concerto: 18 minutes + (Koch cd)
1990: Oboe Concerto: 17 minutes + (Koch cd)
1991: Concerto for Violin, Cello and Orchestra: 17 minutes + (Koch cd)
"One Nation-Reflections on the Pledge of Allegiance" for chorus and orchestra: 5 minutes
1992: Symphony No.3: 19 minutes + (Koch cd)
Bassoon Concerto: 17 minutes + (New World cd)
1993: Concerto for Horn and String Orchestra: 14 minutes + (Koch cd)
Romance for Violin and Chamber Orchestra: 7 minutes
Fantasy for orchestra: 17 minutes
1994: American Concerto for Trumpet and Orchestra: 16 minutes
1995: Triple Concerto for Violin, Cello, Piano and Orchestra: 22 minutes + (Koch cd)
1996: "Peanuts Gallery" for Piano and Orchestra: 14 minutes + (Naxos cd)
"Jubilation" for orchestra: 6 minutes
1997: Violin Concerto: 26 minutes + (Naxos cd)
1998: "Upbeat!" for orchestra: 4 minutes
1999: Symphony No.4 "The Gardens" for chorus, children's chorus and orchestra: 26 minutes + (Koch cd)
2000: Millenium Fantasy for Piano and Orchestra: 20 minutes + (Naxos cd)
Partita for Violin and String Orchestra: 18 minutes
2001/03:"Openings" for orchestra: 4 minutes
2002: "Rituals" for five percussionists and orchestra: 26 minutes + (Naxos cd)
Clarinet Concerto: 28 minutes
2008: Symphony No.5 (Concerto for Orchestra): 24 minutes
2010: "Fanfare: Reminiscence and Celebration" for band: 12 minutes
2011: "Shadows" for Piano and Orchestra: 20 minutes