The reason I used the internal pullup resistors is because i had read that with any CMOS chip, if you leave an input pin floating in this circuit, you could damage the chip. is this not true for the AVR chips?
here is my source for this information, in the comment section someone brought up this point about using internal pullups to prevent burning up the pins. http://www.neufeld.newton.ks.us/electronics/?p=151