I got quite a few replies about the first line thing, enough to see how important it is to all of you. But let's expand that thought a little. While a first line can be haunting for a reader and is the showcase for your novel, it isn't the end. I'm sure people have put down books after the first line--hook 'em good and early, I say--but thankfully it has the rest of the chapter as backup.
One thing I've learned from critiques, a good first line has to be part of a good first chapter. I admit this with some reluctance, but I focused all on the "good" instead of giving attention to "part of." By that I mean, the first line didn't fit with the rest of the chapter. It was from the future looking back, something that doesn't happen in the rest of the book!
So you see what I mean, yes? It's not enough for it to be good. It has to make sense when you look at the novel as a whole, and also when you look at it from a literary standpoint. Let's take one of the quotes from yesterday as an example, "The Call of Cthulhu" because I happen to have it handy.
The first line is "The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents." It's not a stand alone line. The second sentence compounds on the first: "We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far."
The thing about the first line that makes it good is that it introduces the horror that the protagonist, Francis Wayland Thurston, faces and specifically states that the horror is so profound that a glimmer of comprehension is worse than death, the theme of the story.
This is what the introduction of "The Call of Cthulhu" is. The first line leads into the first paragraph, which seamlessly flows into the rest of the story.
Lovecraft may have been a racist jerk, but he knew story structure.