How much current do you require in Arduino and embedded systems projects?
About the worst case current draw I have seen from a higher-end micro controller is about ~200 to 300 mA. This was the LPC2388 (ARM7, 32-bits) with the usb, emc, and all the more power hungry peripherals turned on running at the highest clock speed (288MHz internal PLL divided down to 72MHz). Generally, I would highly recommend going to switching regulators if cost, noise, and complexity is not an issue.