 If you liked
Tenchi Muyou! Ryououki
|
 ...then you might like
Rosario to Vampire
|
Both anime fall into the "harem comedy" category, and have some blatant similarities. Namely, the story centers around an average boy who is surrounded by girls of supernatural origin who fight for his affections. Rosario + Vampire's comedy is more sexual in nature when compared to Tenchi Muyo, but not by much.