I agree with Aifos that it can depend on the situation. However, I think that the plot is more important. The details are supposed to help the plot progress (at least in my opinion). A story can have the greatest descriptions, but if the plot isn’t a good one, then the details become almost worthless. Plus, there is a time to ease up on the detail... I often forget that part of reading a book is imagining the scene. An overload of detail just limits that imagination and becomes more like a boring list than an interesting story. If that tiny spot on the flower’s fourth petal or the tiny chip in a monster’s tooth doesn’t add to the plot, it [i]probably[/i] doesn’t need to be mentioned.

Characters

Depends on the detail. A lot of details the reader/listener can imagine on their own. “The party happened upon a large, dark and seemingly empty room with tiles of marble. Their steps echoed through the space, if something lurked there, it was already watching them.” “The party happened upon a door frame that was 12 feet tall. The actual door itself was missing, but if it had one it would likely take Bob, Steave, Marry, Torgolg the destroyer, and their pet goose Sir Honkers all together to pry the massive door open. But because there was no such door they were able to enter the door freely. Just past the frame was a large and spacious room covered in shadow. The floors were made of a rose marble tile, and gold lined each crevice with master workmanship. The Marble was obviously shipped there from a remote location, as no marble of such color could be found within many leagues. Whom ever built this place was either very wealthy, or a frivolous spender. Sir Honkers reached out his left foot and placed it on the rose marble tile lined with gold. A loud “flap” echoed through the spacious void. Sir Honkers would not be deterred however, and continued to slap his webbed feet down sending vibrations through the air that would surely alert any potential threats hiding in the shadows. If something was indeed hiding there, it was watching Sir honkers, Bob, Marry, Steve and Trogolg the destroyer noisily make there way into the room with rose marble lined with gold.” Obviously I exaggerated. But you can usually make a detailed description once, and then from there on out keep it short and sweet.

Good writing typically doesn’t need lengthy descriptions to be descriptive.

I think it depends on the situation. Sometimes, it’s very important to make sure we know how the monster looks. If we don’t get a good picture, then why it’s so spooky can be completely lost on us. On the other hand, if it’s described in too much detail it can really throw off the pacing, and have the opposite effect of taking us out of the suspenseful moment to talk about the monster’s fashion sense. Generally speaking, though, I tend to prefer when the monster is described in depth, because I love monster design!

C) Gratuitous use of endnotes (à la David Foster Wallace) for the best of both worlds and, if necessary, D) Endnotes for your endnotes.

Secret third option: describing details as and when they appear to drive the plot forward. For example, instead of stopping all the action to describe the monster's talons as they arbitrarily appear on the end of its fingers, describe the way those talons are scraping along the walls as the monster moves ever closer to your protagonist, who now needs to figure out whether to run or fight. Since a monster's appearance only comes into play as it appears for a fight anyway, you might as well use that to your advantage. Does it have a long snout and sharp teeth? It's probably because it can bite the protagonist. Does it have a flexible tail with a venomous spike? Probably to use as a long distance weapon or to attack through gaps in the wall. Does it have eyes on the end of stalks? Probably so it has more range of movement when seeking out prey. Of course, you might not always want to do this. The biggest question to ask is what kind of pace you're going for. If it's a fast paced battle or chase scene, this is probably your best possible approach. But if you want to slow the pace down, probably not so much.