I don't read novels in a day because when I read a book and I really really love it I try to make it last as long as possible so this list will consist entirely of manga since I almost always finish them the same day I start them.
1. Fruits Basket Volume 11: This is my favorite volume of the series although I love them all I feel that it's turning point as well as the half way point of the series. There's a good amount of character, relationship and plot development that happens in this volume. This is also the volume that makes me fear Akito the most out of pretty much all villains because this volume shows that Akito isn't the type of villain that will kill you but the type that makes you wish you were dead. While these volume did have dark moments it also had fun light happy ones and sweet romantic ones as well.
2. Fruits Basket Volume 10: My second favorite volume of the series it's mostly a light fun volume about our main characters having fun at the beach house but there's relationship and character development. Also the mood takes a dark turn once Akito shows up.
3. Fruits Basket Volume 15: This is one of the saddest and funniest volumes of the whole series. It's one of the saddest due to having Yuki's back story about his depressing childhood but it's one of the funniest because of the play Sorta Cinderella, the best version of Cinderella I've ever read/seen although really inaccurate.
4. Fruits Basket Volume 14:This volume gives us Rin's back story therefore making her one of my favorite characters of the series and her mental breakdown which also leads to her and Tohru developing an odd friendship. I also like the chapters dealing with the student council since I always find them entertaining. I also liked how Tohru's character was fleshed out a bit more in this volume.
5. Songs to Make You Smile: The first book on this list that's not Fruits Basket(I probably could have had this whole list be Fruits Basket but I decided to limit myself to 4) but it's buy the same person. This is a collection of short stories that are wonderful and sweet.
6. Tsubasa Reservoir Chronicle Volume 5: This volume finished off the arc that was set in Spirit which seemed like an old fashioned English town and I really liked the arc. It also started the Oto arc which is one of my favorites it's set in a world that has cos play and there are these creatures called oni and Fai, Sakura and Mokona run a cafe. I also love this volume because Sakura almost remembers she knew Syaoran before she lost her memories but of course fate doesn't allow her to remember.
7. Tsubasa Reservoir Chronicle Volume 6: This volume continues the Oto arc and it's just as good if not better than the last volume. This volume includes some insights into Fai's character, insights into Syaoran's past, further development of relationship, the great party were everyone gets drunk expect for Kurogane and Seishiro appears which always makes me happy even though it's usually not a good thing for our heroes.
8. Higurashi When They Cry: Abducted by Demons Volume 2: This volume deals with Kechi's increasing paranoia and his eventual mental breakdown that ends in death as per usual in Higurashi. I love the way this volume handles his psychological state because it makes the reader see were he's coming from and it's just done really well it's even better than it's done in the anime.
9. Shugo Chara Volume 6: A lot of things happen in this volume with both Kari and Utau changing sides in this volume, I especially liked Utau's breakdown and her rediscovering why she wants to be a singer. I also just love this series in general.
10. Clover: This actually includes all four volumes, I just find this story to be so different and interesting.