I don't like the cluttered look of overly-filled bookshelves, but I have a lot of books. Therefore I'm going for more of a "reading room" appeal--cozy, sunlight, and relaxed. Bay window seat required, of course. And a library ladder, like the one Belle has in Disney's Beauty and the Beast.
So here's my vision: Non-traditional library--I want a room that looks like a relaxed sitting room but upon further inspection, you find books....EVERYWHERE....
Here's the beautiful, muted color palette I'd incorporate:
In my head the room is rectangular, so two of the parallel walls will look like this:
One of the walls has a door in the middle of it, with skinny builtin bookshelves flanking the sides and big art pieces on the wall spaces outside the shelves (imagine this photo as though they were on the same wall and not on a corner):
The other wall is dominated by a large bay window with a comfy window seat and colorful cushions piled high. The windowseat walls will have built-in shelves for the books I'm currently reading...Can't find a photo of what I'm mentally picturing, but trust me. It's cool.
Then from the ceiling by the bay window, if it didn't look too weird, I'd put a shelf of sorts for candles, like the one against the wall in this pic. Because really, how amazing would it be to read by candlelight while lounging on your windowseat on a stormy night??!
And if they are needed, I'd put curtains made from vintage flags around the window, so you can pull the flags over the window if you want a little privacy.
THEN for the other two parallel walls:
I'm thinking a nice low bench-style bookshelf on the floor of one entire wall.....
Then, because there is all that wall space from having low bench bookshelves (which I'd cover with cushions perhaps instead of using it as a display ledge), I'd put a myriad of photos, artwork, and pieces collected from my travels on the wall above the benche shelves.
Then against the other wall, I want a beautifully simple, rustic fireplace. I'd make sure that it was big enough so that the top of the fireplace itself is a shelf.
I'd put my favorite books of all time on that shelf and hold them in place with some super amazing vintage bookends...
Then on the shelf on the wall behind the fireplace, I'd hold my collection of antique globes....
On either side of the fireplace I'd put cabinets, where some items would be on display and some would be tucked away from view to hide clutter. Also I'd retrofit one of them to hold wine, because really, who doesn't love reading with a delicious glass of red wine? These are nice options, although instead of paint I think I'd want pretty, warm, rustic, natural wood:
Then I'd put a big fluffy rug (where I can lay on my tummy reading books all day), like this sheepskin...
....in front of the fireplace with a pretty carved trunk for a table, like this:
Around the table I'd place big huge comfy brown leather chairs and couches....here's a good example: