I still prime Hardie Board siding even though it is pre-primed. This way I know everything is perfect. The best primer I have found for Hardie Board is Zinsser 123 acrylic primer.
Any good exterior 100% acrylic satin paint can be used. The brands I like are Devoe, Benjamin Moore, Porter and Sherwin Williams. All of these brands have good paints as long as you choose their best line.