The example code that ships with arduino currently uses a switch connected to 5V, with a resistor to ground.
This was so you don't have to explain things like the switch pulled the digital in LOW, so digitalWrite HIGH to turn the LED on(it was counter-intuitive to a lot of people).
It feels to me like part of the dilema here is a choice of where you put that bit of complication as you start - a more complicated external circuit (an extra component and more wires), or more complicated code (if low write high, rather than if high write high, and possibly another parameter).
Having a simple code link between switch and LED in the button example, makes introducing pullups soon after more complicated, as you need to reverse the logic of the code/hardware as well at that point.
Having an external resistor at the beginning feels like more preperation for the road ahead to me (it will be needed for other circuits), but I know different people will have different takes on it.