I'm a lefty, although I'm also a bit ambidextrous as most lefties are (I write, hold a bat/racket with my left hand but throw with my right hand), so I'll be using my left hand for using the wii-mote, but when it comes to nunchuk+wiimote I'll probably hold the nunchuk inmy left and the remote in my right because I'm used to it. But I'm not too fussed 'cause I can adapt pretty easily anyway...
EDIT: Lefties are superior. Look at cricket, almost all international openers are left-handed and there are many more examples of great left-handed people in the world besides the ones Fierce has mentioned (as he has basically only mentioned guitarists) such as:
Osama Bin Laden
Jack The Ripper
Abu Musaq al-Zaqawi