Re: USB port power supply doesn't match RPi spec
On the RPi there is a 750 mA PPTC (polyfuse) in series with the microUSB power port. On the schematic this (F3) is labelled with a value of 1.1A but on my board it's 750 mA.
There's no need for a power supply with a current rating in excess of 750 mA, because if the RPi was actually drawing that much current it would trip the PPTC and wouldn't work anyway. There's no way that it can actually be drawing 1.2A through that port if you're using unmodified hardware. (Assuming you're powering it via the microUSB port and not injecting power via the +5V pin on the GPIO header.)
However, if you want to add extra peripheral devices onto the USB ports, and you don't want the extra complexity, cost, size and cable mess of adding a powered USB hub just to run two USB devices, you might remove and upgrade the PPTCs (especially F1 and F2, the two in series with the two USB host sockets' 5V rails, since they're only rated at 140mA each and therefore you can't use any USB device that draws more than 140mA) and if you replace them, and replace the 750mA PPTC on the 5V input with a higher-current one then it does make sense to use a power supply with a higher current capacity.