Clannad Mines would have to be Rosario + Vampire. For some reason I grew such a strong bond between these characters and I have no idea why. Even though the anime was cancelled I and never had a season 3, it's still an anime I'll forever cherish.
KamiSama I watched it seems just about every harem series out there. Even Hentai. But I couldn't really single one out off the top of my head.
Kamina BetterThanYou wrote My favourite harem is my own Loading Image Thanks for the nightmares and 3 weeks of therapy