When you are writing a book (or reading one for that matter), how important is it to closely detail the scenery or the setting? Does it just depend on the setting or the type of story, or is it always important?
I agree with the spirit of Kate's answer, but it glosses over an important point. Ultimately, it doesn't matter what you are describing as long as it's interesting and adds to the story. If you are writing a romance and the characters' mundane setting is what they are trying to break away from with their affair, then it is important the reader understands that. If we are shown why they hate their cubicles, we will be even more likely to be able to connect with them when they start their passionate affair.
But just because something is actually mundane, doesn't mean it can't be described in a interesting or engaging way. This is really the goal of every aspect of writing. There have been plenty of seemingly interesting plots or characters that are ruined because of boring language and uninteresting details.
The best definition I've heard of exposition is "It's only exposition when you realize it's there." As long as your details and suggestions don't stand out (a much more difficult task than I'm making it sound, for sure), then it's probably doing it's job.
I am actually a big fan of thinking of setting or location as another character (though often a minor character). All the same rules apply, including understanding it's motivation, history, goals, etc. Even if all these details don't make it into your final story (and most probably shouldn't), it's important for you to know what they are.
One last point: make sure that your setting is being described from a consistent point of view. This is easier if you writing in the first person (at least in theory, any way). But if you are writing in third person, be careful not to make observations or add details that are outside the scope of your narrator's knowledge (this is really part of a larger issue of finding your narrator's voice and vision).
I think it absolutely depends on the type of story, and on the writer's goals.
If you're writing a romance, and it takes place in a mundane office building, why waste space on describing the cubicles? If the setting doesn't advance the characters or the plot, gloss over it.
On the other hand, if you're writing something set in another world, and you want your readers to know what it's like to live in that world, you're going to have to spend a good bit of time on description. Hopefully you can work at least some of the details in through dialogue or hints in the narrative, but I'd much rather read a little straightforward exposition than a clunky, unnatural stretch of dialogue in which characters describe things that they really should be taking for granted.
When it comes to reading, I think there's a range of preferences. I know that I skim description, especially if it's set off in distinct blocks of text, but I know others who feel that they can't enjoy a novel unless they they can see every detail of the setting. Just one more thing to make the author's job impossible...