 If you liked Gravitation |  ...then you might like Gakuen Heaven |
Shounen-ai with a solid plot: Gravitation and Gakuen Heaven fit the description. Gravitation deals with the world of music, fame, and a very stormy romantic relationship between male leads; Gakuen Heaven is a school drama used to explore the considerably calmer involvement of two boys in love. Those who thought that Yuki and Shuichi were too at odds with each other to be believable should check out Gakuen Heaven; those who thought that GH was simply not random and angsty enough should give Gravitation a go.