I know some people who freak out when their chapters' lengths vary too much, but quite honestly I don't mind (and think they're weird :p). I don't like lots of ultra-long chapters, though, because I usually read before bed, and 60-page chapters can be annoying to negotiate when I'm getting sleepy.

I'm okay with no chapters, like in most Discworld books, but if the story is very engrossing then the lack of chapters makes it difficult to go "okay just to the end of x and then I won't turn the page and I will go to sleep damnit" but that is quite obviously something an author should be proud of, so!