On my girlfriend's 2002 Buick Century, you can turn off the head lamps after they have come on automatically, by manually turning on the head lamp switch, then turning it right back off.
On my 2001 Z28 Camaro, you cannot turn the head lamps off if the car thinks it's dark enough outside. You can of course turn on the lights manually even if it is bright out, but that's not what you are asking for.
On my 1985 Dodge Ram pickup, the lights turn on and off via the manual switch only. This is the way I like best.