This book needs no introduction. It is one of the touchstones for the entire post-apocalyptic strain of movies and literature. As such, I delayed reading it because I assumed I'd already seen it all. Actually, there were a lot of new things in it, probably because King did them so well in this one that the genre moved away from it as a result. The book itself is divided into three "books," which I think of as 1.) Decline and survival; 2.) Community; 3.) Confrontation. From my post-"post-apocalyptic" reader's perspective, it gets better as it goes along. The version I listened to was the expanded version put out in the 80's, and I think I'd recommend reading the original version, because I didn't feel the need for the additional character moments.
The real value of The Stand comes from its spiritual side. Especially in Book 3, the characters encounter some genuine spiritual formation. Even though I disagree with some of King's theology (especially his theodicy), the mere fact that he has a theology and thinks it's important enough to drive his book is a source of astonishment to me.
I also want to remind anyone complaining about the way LOST ended to compare their complaints about that series to the near-universal praise for The Stand. Both sagas are telling stories with a similar shape, and when I put the two series side by side, I actually prefer LOST's plot choices (in every area but the "spiritual formation" one that surprised me most in book 3). I think you can argue that LOST was clumsier in how they presented the mythic elements, sure, and introduced them too late to the story for most viewers' credibility meters -- but both stories start with science and end with spirit. I just think the conventional wisdom that LOST somehow failed is showed wrong by comparing it to The Stand. They are similarly successful in terms of story, which is the most important category to me.
In the end there's too much extra stuff and too little of the theological "meat" that really makes the story worth it for me to rank The Stand in the upper echelon of King's work (which would be 11-22-63, Joyland, and The Green Mile). But it's awfully close to that pedestal, and if I had read the edited version it may have made it.