Elizabeth Moon
--The Deed of Paksenarrion [female main character, asexual]

Katherine V. Forrest
--Daughters of a Coral Dawn [main lesbian characters, lesbian utopia]
--Daughters of an Amber Noon [main lesbian characters]
--Daughters of an Emerald Dusk [main lesbian characters]

Jo Walton
--The King's Peace [female main character, asexual]
--The King's Name [female main character, asexual]

Ellen Kushner
--Swordspoint[gay main characters]
--Fall of the Kings [gay main characters]

Orson Scott Card
--Songmaster
--Ender's Game

Nicola Griffith
--Ammonite [lesbian main characters, all-female planet]
--Slow River

...more to come...