I agree, cocoa powder does give the best but if you want chocolate; Lindt makes some of the best baking chocolates I know of but I can never find them. Instead, I buy some of the Swiss imported Nestle chocolate at the company store where I work (54%/72%/and76% cocoa butter content). Both are quite rich in flavor and melts beautifully over a double boiler.
Callebaut chocolate is my choice. Bittersweet is my style of choice as well. I can't remember my brand of cocoa powder off the top of my head. I also use Ibarra chocolate for a groovy flourless chocolate cake with a twist.
I am in love with Dagoba's cocoa powder. They're a fairly new chocolate maker in Oregon. Organic and fair trade is that matters to you. It smells heavenly and the taste is a happy medium, lots of flavor without being too dark and bitter.