planecrazy29:
My take one your question about the switch:When the switch is open, there is infinite resistance to +5v. Current will always take the path of least resistance which in this case is through the 10k resistor to ground. This holds the pin input low.
When the switch is closed (pressed) there is zero resistance to +5. Current will always take the path of least resistance which in this case is through the switch to +5 pulling the pin high.
That's correct, but pull-down resistors are a bad idea - you should have as few wires going to the 5V supply as possible in your circuit. Bad things are far less likely to happen if you do that (plus, using internal components instead of external components means less chance to connect things wrong).
Don't believe me? Connect the two versions up on a breadboard (internal pullup vs. external pulldown) and compare them before you hit reply...