I prefer the -ai genres and Yaoi. Shojo ai is wonderfully done with just enough of a hint. Some of those storylines seem to have the deepest connections of all, even if it leads to a hint of a sex scene to come and fades to a different line. And... I love seeing boys kiss, so I like shonen ai.
Sometimes, their connections can match the shojo ai ones.
And Yaoi because... There's something very sexy about watching two men engaged in intercourse. I detest it when it's without story though or if I can't find one. Initially, I liked Level C for example because I saw a storyline. When I looked closer, I don't get the same impression anymore, so my initial liking dropped it to fifth place. Sweet Revolution was my favorite one shot while Junjo Romantica is my favorite series. I'm going to cry when book seven of it comes out and it ends...