Most devotees of crime fiction read for story (plot) and character. That's the baseline. If you don't have that, you don't have anything.
But there are plenty of (choose one: good - likable - interesting - conflicted - complicated) characters out there, and at the end of the day, there are only so many plots. You can find lists all over the Internet of the six or seven plots, and some distill this list to two: "Someone goes on a journey" and "A stranger comes to town."
So that leads us to those other factors that make for a fine read. There's that all-important "good writing," so easy to require but so hard to define (though I've tried here on Mysterious Matters). Pacing is important, too; and I am always drawn to manuscripts that seek to do something new, different, brave, innovative.
And to that list let me add something that always makes me stand up and take notice: VOICE. And there's nothing that knocks my socks off like a voice that jumps off the page and punches me in the face. Such books are rare; sadly, we're not seeing many really fresh voices in our genre these days, but that doesn't mean they aren't out there. (In fact, I just ordered a few recently published books that have a lot of potential in this area, or at least it seems to me based on the Amazon previews.)
And I just finished a book - Liza Cody's MONKEY WRENCH - whose voice made me gasp with pleasure. If someone had tied me up and forced me to make my Top 10 list of breathtaking narrative voices, Liza Cody would have been on my list. There was a time when I regularly gushed about Cody's first Eva Wylie book, BUCKET NUT - the first of a trilogy starring Eva Wylie, the professional wrestler who goes by the name "The London Lassassin." But it had been a while since I thought consciously of Liza Cody. Then, I was talking with my wife, who recounted a tale in which someone "threw a monkey wrench into the works." That got me thinking. "Monkey wrench, monkey wrench, great title for a book... wait, there's already a book with that title... a book that I love..." And then I remembered that while I've read BUCKET NUT a dozen times (and often recommend it to aspiring writers), I realized that I haven't reread the other two books in the triology (MONKEY WRENCH and MUSCLEBOUND). And so... I opened MONKEY WRENCH again and found myself immediately drawn into its vast pleasures of language.
For those of you who don't know Eva Wylie, she is the adult daughter of a former prostitute who is bound and determined to take the world of wrestling by storm. And she's a mystery. Is she a person of low functioning intelligence, or a person of high intelligence with some sort of personality disturbance or learning disability? These books were published, I think, at a time when the world wasn't quite aware of Asperger's Syndrome (if, indeed, that's how Eva would be classified today). Eva narrates these books in first person. She just wants to be left alone (like Romulus Ledbetter in George Dawes Green's The Caveman's Valentine, another triumph of voice), but she's forever getting sucked into the problems of others. Watching Eva muscle her way through these books - simultaneously spot-on AND clueless in her perceptions - is a marvel to behold. On every page of MONKEY WRENCH I found a delight: whether a word, a sentence, a scene, or an insight. This is fabulous and brave writing with a voice to bring down the house.
As I finished the book and prepare myself to read the third of the trilogy, I find myself sad that there are no more. Cody stopped her series after the third book; and I wonder if this is one of the reasons that Eva remains as fresh today as she was in the early 1990s. Cody didn't stretch Eva Wylie to death; my guess is that she realized that the perfect conception of Eva made her a credible heroine for three books, and that more than that might have taken a marvelous creation and turned her into a joke. So, for all who have not met Eva Wylie -- run, run to the nearest bookseller and treat yourself.
And a publishing aside: I was reminded that Cody was published in these glory days by Mysterious Press. What a publishing house! I would have given my eye teeth to work there back in the day. That legacy inspires what I do every day.