Hard to say... I've liked most of what I've had so far. Chocolate Habanero and Jamaican Hot Chocolate for heat, Orange Habanero (for that "habanero" flavor), Hot Lemon (nice heat would go well in foods as a replacement for cayenne), Red Dominica Habanero for pure size plus taste, Burkina Yellow for cool shape... hell, even Tabasco seems to be excellent for powder.
Lots more still to ripen, examine and try out... one (each) new ripe Mustard Habanero, Congo Trinidad, Congo Yellow, and Harold's St. Barts are ready, and I've got a Bhut turning orange (Yay! My first superhot!!!).
I wasn't too thrilled with the Amazon, Datil, or Peach Habanero (though the Peach was, IMO, the best of the three). Not amazed by the Pimenta de Cheiro either, but I intend to try making powder with it; I have a feeling that'll turn out well.