High quality switching 'wall wart' AC to DC 5V 2A wall power supply manufactured specifically for SparkFun Electronics.
There are crappy wall-wart power supplies, crappy switch-mode, and then there are these. Sparkfun did a great job sourcing these good quality 5V 2A switch-mode power supplies. Much more power efficient than the original style linear adapters, and a whole lot less noisy and more safe than "bargain" switch mode power supplies.
These are FCC/CE certified, and replace their older 1A version.