I own, but haven't read, the X-Wing series, but I know the books are tremendously popular, so I probably should, eh? I've only read the Thrawn trilogy through once, but that was roughly a year ago, and I was thrilled with them. I'd love to read them again. The New Jedi Order? Was that the post-Thrawn trilogy series with Admiral Daala and the Sun Crusher? I read those, but Anderson is, if you don't mind me saying, a shit writer.
My favorite book from the Expanded Universe has to be Shadows of the Empire. It has numerous shortcomings, but I first read it when I was like, five, so it bears a certain nostalgia that I can't ignore. Plus, Xizor is amazing.