I've read pretty much every book released in the EU and some were hard going whilst others were close to the spirit of the original Star Wars. As mentioned above, the Thrawn Trilogy, which kickstarted everything off in the early 90s, is good reading. Zahn seems to understand the characters a lot better than those who subsequently wrote stories. Thrawn is an interesting character, a non-human in the company of humans and leading them. He had an interesting way of reading enemy tactics.
The X-Wing series, as I've written elsewhere, were also good books to read and I've re-read them many times. It's good to be able to concentrate on fringe characters and bring them to the fore. Wedge finally got a series to himself, had a backstory (of sorts) and was able to be more than 'Wedge Antilles, the only other character in all of the original trilogy movies'. More than anything, I feel this series of books above all written so far would translate well to a set of TV movies. There is an established set of central characters, similar enough to evoke warm fuzzy feelings, but different enough not to be labelled as a 'Luke clone' or 'Han clone'. The established characters do make appearances, but by-and-large, this is a Wedge series and I think it benefits greatly from having a set of characters who weren't as tightly defined by Lucas.
Ok, so this thread is about the good stuff in the EU...however, along with the good comes the bad and the ugly. The bad stuff? Well that might be the Yuzhong Vong invasion...a series of books that took far too long to come to an end, killed off everyone's favourite 'shaggy dog' and generally created a clone of Vader. Ugly? Well that would be the rise and fall of Jacen Solo. He seemed to be set to 'clone Anakin Skywalker' but by 1000%...only this time he was 'fighting to save the universe for his daughter' only he didn't get seduced by a great user of the Dark Side, but a bit part character who was killed off in the comics at least twice and was a rebel pilot to boot! Jacen really had to be a bit weak willed to be driven in this way...to me at least! Not only that, but he really did become quite whinny in his manner toward the end...do all Jedi who fall end up with this attitude?