I started writing a reply, but my thoughts are actually big enough for a whole post. In fact, this is a perfect time for this post as I recently did some rearranging when I went through looking for my TBR books. I find it's a good time of the year to cull out some for the donation pile.
The Current Situation
I have three (well four, I guess) basic shelving areas for books at this point in time.
Area 1: Oversize books are just stacked up on our mantle. We don't have a coffee table, so they end up here. Most of the ways to fix my current problems really involve buying more furniture, which is not currently in any budget...basically ever. I'm okay with this coffee table book stack for the most part because they're accessible and people could look at them if they wanted to.
Area 2: At some point a few years ago, probably to clear out room at home, I moved ALL of my poetry books to school. I don't know how I feel about this after reading Station Eleven. What if the superflu wipes us all out and someone comes through my house looking for poetry books, and they're all at work? Sigh. When I want to read poetry at home, I usually use the Poetry Foundation app. So..for now, they're staying at school. I try to keep all my teaching and work related books at school. Books for my grad school classes I keep at school when I'm done with them. I have tons of room at school, so I might as well use it!
Area 4: This is the biggest problem becomes readily apparent: I really *don't* have enough
As for their current arrangement, the top 3 shelves on each are fiction, and it just goes straight across the two rows. This is straight alphabetical, with paperbacks mixed in with hardcovers. I don't think I could do color because I have so many books by a same author, and it would drive me bonkers if they were all in different places. Graphic novels are together, although I don't have that many, so it's easy. The bottom 3 rows are non-fiction, and they're loosely organized by subject. So literary history, biographies, all the James Joyce is together. Then any science books, history, etc. The bottom left is all cookbooks. I mean, I hardly use cookbooks anymore, mostly the internet, so that be space I could reclaim at some point.
I would LOVE to buy new bookcases (or get built-ins...living the dream!) As you can see, these are the fairly crappy Billy bookcases that I've had for at least ten years, but buying all new bookcases---even IKEA ones---would be too expensive. Here's one I've been lusting after for years. Wouldn't this look AMAZING in the place of the Billys? The problem with that is that I'd totally be buying it for the looks, but I'd have way less room for actual books. Therefore: no cool round bookcase. [PS. You can see I put a shelf on upsidedown when I was building the Billys. Look under the cookbooks. You can see the underside of the shelf is facing up. It's charming! Heh.]
I have thought a lot about moving these shelves, because this area gets lots of direct sunlight. It's not like my books are worth anything, but I can see how the spines are becoming faded. Sigh. The only books I actually moved are my Harry Potter books. Those are downstairs on the desk. As it is, even though we have a huge place, I don't have a whole lot of places for other bookshelves given the current furniture situation. I could have done it downstairs on that big wall, but it became the map wall, and I love that too much to give it up.
One look I really do like are lots of low shelves, and that's probably something I could get away with...but then we're back to buying bookcases, and that's just not going to happen anytime soon. Of the ones in the link you sent, this is my favorite. If I could have floor to ceiling bookcases, I'd do it in a hot second.
The REAL problem: Let's be honest: there are books stashed all over the house. I try to corral them upstairs and move them back onto the shelves, but they are *everywhere*. For some reason, I just keep buying them. And getting them from the library. And reading on my Kindle. You'd think I just loved reading or something!