Shadows Of The Empire
The Thrawn Trilogy
The Jedi Academy Trilogy
The Courtship of Princess Leia
The Bounty Hunter Wars
Darksaber
Planet Of Twilight
Tales From The Cantina
And I really enjoy these as well:
The Blackfleet Crisis Trilogy
The Crystal Star
The Corellian Trilogy
The Hand of Thrawn Duology
Outside of those I'm not a fan of much, though I do still need to catch up on the Han Solo trilogy