I tend to play better with black. Most of my favorite cards are black, and I tend to see the positive side of a card even if it seems to have a crippling negative side. I run a really good Hellcarver Demon/Eldrazi deck (which I call 'Helldrazi") that shows this kind of thing very well. All of the black cards have downsides but if you utilize it properly, it doesn't even effect you. I also really like blue and red is pretty good too. I tend to play really bad with white or green, but I have been meaning to change that a bit, so that I can use some cards I've kind of been neglecting.