this is an amazing series
* Jedi Academy 1/3: Jedi Search Kevin J Anderson
* Jedi Academy 2/3: Dark Apprentice Kevin J Anderson
* Jedi Academy 3/3: Champions of the Force Kevin J Anderson
Haven't read any of the pre return of the Jedi books, but read all the books after, apart from the x-wing series.
Then if you like that series I recommend the New Jedi Order series. its a universe fight against an alien race from a different universe. Its very good, lots of insight into the force.
* Vector Prime
* Dark Tide # 1 : Onslaught
* Dark Tide # 2 : Ruin
* Agents of Chaos # 1 : Hero's Trial
* Agents of Chaos # 2 : Jedi Eclipse
* Balance Point
* Edge of Victory # 1 : Conquest
* Edge of Victory # 2 : Rebirth
* Star by Star
* Dark Journey
* Enemy Lines # 1 : Rebel Dream
* Enemy Lines # 2 : Rebel Stand
* Traitor
* Destiny's Way
* Force Heretic # 1 : Remnant
* Force Heretic # 2 : Refugee
* Force Heretic # 3 : Reunion
* The Final Prophecy
* The Unifying Force
* Dark Nest # 1 : The Joiner King
* Dark Nest # 2 : The Unseen Queen
* Dark Nest # 3 : The Swarm War
Also the
The Hand of Thrawn Duology (19 ABY)
* Specter of the Past by Timothy Zahn
* Vision of the Future by Timothy Zahn
is well worth a read.