I don't think hentai animes are for really sick people. I'm not a sick person. Anyway, the truth is I don't like ANY hentai, some are just disgusting and disturbing...but there are "decent" ones too
Soo, I don't think I have a favourite...but, I'll say a very good anime is Death Note.
Other than that, I loveee yaoi animes, and I think I had already seen them all. I don't really remember the plots though