It seems that several people (myself included) are having great difficulty getting different wi-fi adapters to work reliably with the Pi. Some adaptors seem to require excessive amounts of power and a mandatory powered USB hub, others require tricky configuration steps, and some even require Kernel modifications.
Is there a low power compact usb wi-fi adapter available that doesn't require any external power and is compatible with the Raspberry Pi and the greater majority of images (such as Raspbian, Arch Linux, RaspRazor, RaspBMC and OpenELEC) out of the box? If so, where can we buy it from that will ship internationally?