What mr.Viswa was asking is is it bad practice to write 1 to a port pin which already is 1, (same for 0's), and does it influence power consumption. No, it's not bad practice, and no it doesn't affect power consumption.
The strong pullups Kai mentions are only turned on for 2 clock periods after a low to high transition in the port latch. If you write 1 to a latch which already holds a 1, there is no 0 to 1 transition, and therefore, the strong pullup is NOT switched on if you do this. Read the "Bible". Also, the "Bible" states quite a different reason for the strong pullup to be activated while conducting normal I/O than charging capacitive loads.