It's easily his most popular and widespread novel, which is why it always gets brought up first when people talk about his novels. It was probably the introduction to Gaiman for a lot of fans, and it takes his mythology-in-the-modern-world ideas all the way, making for an interesting concept.

But in terms of all his novels, I probably wouldn't even rank it in my personal top five. It's good, but there's something holding it back from being great. I think that Gaiman's deceptively simple writing style is is somewhat less suitable to gritty adult works than it is to all-ages work and comic book work. It's best when used for understatement, humour, and wonder.

My favourite Gaiman novels are his all-ages stuff. They're written so that they're suitable for younger readers, with no obvious sex or swearing, and the main characters are often the same age as the marketing demographic, but the writing remains highly intelligent and his style works for anyone, child or adult. These books are still dark and wondrous, which is why I love them.

If I had to rank the Gaiman projects that I've read, I'd go like this:

1. The Sandman (comics)
2. The Ocean at the End of the Lane (novel)
3. The Graveyard Book (all ages novel)
4. Stardust (all ages novel)
5. Coraline (younger reader novel)
6. Smoke & Mirrors (short story collection)
7. Good Omens (collaborative novel)
8. 1602 (short comic series setting Marvel superheroes in the year 1602)
9. American Gods (novel)
10. Fragile Things (short story collection)
11. Neverwhere (novel)
12. Anansi Boys (novel)