Gamepads are the worst way to control an FPS ever devised - I might get used to it, but I'll never like it. The Wii controls I could...
i got used to it as i for some time only had an xbox for entertainment (running on a travel 7" tft looks like its too small to ever be usefull but it actually seems huge when sat nigh on infront of it)
but the wii rifle adapter looks brill ... if someone would make a gizmo that enables it to work out of the box on the pc it would be brill ... but at the mo you need an ir bar the wiimote and nunchuck and iir bluetooth dongle