It's not shonen-ai/yaoi/BL (dude, try the manga), it's not exactly shonen (thank you, anime), it's most definitely not shoujo, harem, etc. It's also not really general, so due to demonic butlers, it's supernatural.
Kuroshitsuji is one of my favorites now. It's <3
I love Grell Sutcliff. Resident Transsexual/Homosexual, I'm not sure (but s/he "atashi" which is feminine so maybe trans?). His interactions with Sebby are <3.
I love Ciel Phantomhive. He is so cute~
I love Sebastian Michaelis. He makes things funny. Especially in relation to Grell.
I do not like Cute Lizzy. But I adore the wife of the queen's watchdog, Badass Lizzy.
Madam Red was amusing.
The other servants make seeing the mansion awesome.
Alois Trancy made me cry.
Claude is a mean jerk. I dislike him.
I do not like Hannah. :\