Let's see.
A series based on the Thrawn books (5 years after Return of the Jedi) would be just *AWESOME*. It would be the best as well, as those were the best of the best SW books, and also were the first authorized novels to come out after the movies.
Unfortunately, most of the actors (especially Mark Hamill, aka Luke Skywalker) are too old to play 5-year-older characters.
New Jedi Order would make the most sense. I loved the New Jedi Order series with the exception of Vector Prime (which they could easily redo). It's a whopping 19 books long I believe, so a TV series could last a long time. Plus, while a lot of the original characters are still there, (such as Luke and Leia and Han and C-3PO and R2-D2), they're SUPPOSED to be 25 years older, so they could still use the original actors (that haven't died yet, lol). Plus with all the new characters (Han and Leia's 3 children that are teens, Chewie's nephew Lowbacca) to fill in, it would be an awesome series.
Though the Yuuzhan Vong on TV might give people nightmares