Luggage and bags:
Girls, don't bring too much "stuff" with you to Pak. Women's clothing is so cheap and you will want to be sensitive to the way women dress in Pak, so buy your Shalwar Kameez when you arrive. They are so comfortable and cheap. The colours will blow your mind too.
Clothing/Shoes/Weather Gear: Shoes galore! So much available from markets.
Toiletries and Medical Supplies: I would take some Imodium next time i go. Paracetamol is available.
Pakistan is a land of incredible contrast. My trip took in Islamabad, Skardu and the Glaciers of Baltistan, going from 38 degrees (celcius) dry heat of Islamabad to the 'miuns something horrific....blowing snow of the Baltoro Glacier'!
Most people have an image of a hot dry country, but really consider you packing if you are doing the all-round trip.
Photo Equipment: I brought a polaroid filter for my camera to take pictures on the glacier where thre was little contrast with so much glare.
I found it helped bring out the features of the landscapes better (compared to the phots I took without it) but just beware - I 'over-did-it' a bit with some of the photos and got almost black sky! (The joys of altitude photography!)