This may infact be a stupid question, but I have yet to find the answer in my searches so here it goes....

If I am not connected to a wireless access point would it save battery life to turn the wifi reciever off? Would it make a difference if there WERE networks in range (even if I had no intention of joining them)?

Yes, it does make difference.

If you turn the wifi off, you'll prevent it to repeatedly scan for available networks which is battery consuming.