Defense of the Heart: I've yet to meet a player that disliked this card. Even when it's about to fetch two of my opponent's scariest creatures and I have no real defenses, I'm all, "Dude, that card rules."
I dislike that card!
Seriously, searching your library for two creatures and putting them into play is just sooo nasty..
I don't care which creatures you fetch, I'm always wondering why someone would put such a all-or-nothing card in their deck.
The first thing I did after Legacy came out was put together a Defense of the Heart deck. It's casual credentials are up to snuff, good nomination. Rancor may be too good and too specific, but I think it makes all sorts of green beatdown decks a lot better, and green beatdown decks are almost always casual because they can't actually win tournaments. I'm going to delay on my nomination for the moment, but I will say that Legacy was a very good set, lots of good commons and uncommons, and very few useless rares.