That depends on what u want to read.
Do u want to read something prior to the OT?
Or something in between the OT?
Or something after teh OT?
I haven't read any books before the OT so there u would have to hear with someone else, perhaps JP.
If u are looking for some books in between the OT I would suggest Shadow of the Empire (even though I havent read it), or perhaps some of the Bounty Hunter books. Tales from Jabba's Palaca is also worth checking out.
As for books after the OT I would suggest u start to read the Heir to the Empire trilogy written by Timothy Zahn. Then perhaps continue with the Jedi Academy trilogy by Kevin J. Anderson. After that u should read the sequel to the Heir to the Empire trilogy, The Hand of Thrwan duology, also by Timothy Zahn. Then u should go on to the New Jedi Order books.
This is just what I thinkis the right way to read them, do anyone disagree?
There are of course some other books which does take place both in between the OT and after the OT, such as the X-wing series. I haven't read them, yet, but I've heard they are supposed to be good.
So did this help?
I have read all of the adult novel in the Star Wars series (except Hard Contact and Med Star 2) and I make the following suggestions. If you want to start with the prequel era then start with Cloak of Deception. Then follow the timelines all the way through Ep III. Look in books for the timelines. Just look at the front of the books at the book store. This era will take you through the prequel movies and the Clone Wars.
However... if you want to start with the original trilogy. Truce at Bakura takes place three days after Return of the Jedi.
There are also stories that take place during the Classic Trilogy as well. Any new non-Clone Wars novel will have the timeline.
You could also start with the New Jedi Order.. but there may be a lot of characters you would be unfamiliar with...
hope this helps!!