I have a small addiction to purchasing specialized travel gear. We would not be considrered "backpakers" but do prefer to travel light with the ability to carry our luggage and have the versitility that standard suitcase style luggage does not offer. With that in mind, I set about finding the most fitting pieces of luggage for our style of travel. I ended up purchasing two, MEC, Pangea 75 tavel backpacks (Available at MEC). Each armed with one of these bags my wife and I have used these bags as weekend luggage, snowshoeing day hike bags, and for a three week trip around Italy.
There are two parts to each one of these bags. The first is the main "suitcase" style backpack. This bag is equiped with 60L storage and has a lower portion to store a sleeping bag, shoes or laundry. There is a detachable toiletries portion and numerous small pockets for all your little things. There is a flap to hide the straps allowing you to check the bag without fear of having the straps ripped off when being loaded or unloaded on a plane, train or bus (I once worked at the airport as a luggage handler and have seen first hand a bag be destroyed because of loose straps). We both found this bag to be more than big enough for all of our luggage. The straps and harness are very comfortable allowing for a couple kilometre walk to your hotel or hostel.
The second part of the bag is a detachable carry-on size backpack (15L). This bag is big enough for a nebook, Kindle or Ipad as well as a change of clothes and a jacket. When combined the two are a little top heavy. The day pack is surprisingly big and comfortable to wear.
The only draw backs to these bags are the zippers are not lockable and the daypack is to small to have a waist belt. The major pluses are the versitility of the bags, the comfort of them as well as the overall design. We are about to embark on a trip to New Zealand and Australia for a year or two and I will update how they stand up to the punishment of the outback.