I am greedy. I want both plot and characters to be great.
I have gone through short phases in my life where I looked for male aythors, or female authors. This was because I read several books by that gender of author and really liked them, but I soon discovered that there were pretty much as many of each gender that produced either trash or treasure.
I like a good plot, a satisfactory conclusion, characters I can relate to, a smidgeon of romance is generally a good thing, but not a necessity, humour/wit is always a bonus, although again not a necessity.
Cliffhanger/to be continued endings really put me off as do cardboard characters who only focus on their mission.
As an aside, I have a friend who prefers books where the authors name is bigger than the title on the book cover, as he figures they must be good
Helen