When ten-year-old Negi Springfield graduates from magic academy, he is given a rather unexpected training assignment - to teach English at an all-girls high school! In order to become a master mage, Negi must tutor a class of thirty-one pupils while keeping his magical powers hidden. Because of his young age most of the girls struggle to take him seriously, treating him instead like a cute child. However not all everyone in the class is happy with their new tutor. Kagurazaka Asuna has a crush on the teacher Negi is replacing, and when she discovers the boy's secret she decides to make his life as hard as possible. Will Negi be able to complete his training and realize his dreams despite all the obstacles that lay ahead?
Urashima Keitarou is a loser. He's failed the Tokyo University entrance exams two years in a row, and his parents have finally kicked him out of the house. Penniless and destitute, he travels to his grandmother Hinata's inn, hoping she'll put him up until he can get into Tokyo U and fulfill his promise with his childhood sweetheart (whose face he can't even remember). Unfortunately - or perhaps fortunately - it turns out that the inn is no longer an inn... it's an all-girls dormitory, as he discovers in his typical blundering fashion by grabbing an eyeful and more of every girl in the place! Narusegawa Naru, a fiery-tempered high school student and the first victim of Keitarou's lewd bungling, wastes no time doling out brutal punishment and preparing to kick him back out to the street. But wait! A letter has come from grandma Hinata, and Keitarou is to be the dorm's new live-in manager! Is this a blessing from heaven, or has he been cursed to a living hell?
Like RahXephon, Escaflowne is another series that deals with the fate of humanity, and a hero must try to save the world by piloting a huge medieval robot called a Guymelf. The animation is very similar to Escaflowne and the story is epic as well.
If you like Negima, You'll Like Love Hina because both have a guy surrounded by girls over the protagonist of Love Hina (Naru Narusegawa) as being Asuna
Negima is Love Hina kicked up a notch. The stories are quite different, Love Hina being about getting into college and Negima being about a 10-year old mage becoming the teacher (not magical, just regular teacher) of a bunch of middle schoolers. But the important thing with Ken Akamatsu's works are the girls, and Negima has about 10x as many. The "main" girls in each are also quite similar in temperament.
The two are almost the same with Negima being more action-packed and Love Hina being a more indepth story.
Both done by Ken Amatatsu, Both Harem mangas, Love hina is more of a comedy where Negima! is a fantasy and action manga.
Assassination Classroom and Mahou Sensei Negima both deal with classrooms where each character is important. The teacher in both are each highly active with the students of their class as well. That is the big similarity between the two, so if that is something you like then check out the other.