The last game I played, I found out that I love my B/R deck.
As for Red, low cost damage spells, abundant random chance (Burning Inquiry saved me), and some decent creatures, there's nothing not to like.
Black. Well, I was a little skeptical about continuing with black, after a rough time with it. I was VERY skeptical after my Vampire Nighthawk was sent to the graveyard immediately after sending it into battle. But after receiving Rise from the Grave at a most opportune time, coupled with Unholy Strength, it became quite a force. All the "no questions asked" destruction (my favorite card, Doom Blade, and my second favorite, Mind Rot), and the healing yourself at the expense of others, have made me learn to love the dark.