I know quite a bit about backpacks and just got through some extensive shopping for one to use just for travel (I've got 3 others I use for backpacking).
Northface used to be a top notch company but has been bought out (can't remember by who off the top of my head) and their quality has suffered for it. I wouldn't by anything new from Northface. Their old stuff (pre-buyout, around 5 yrs or older) is still good though.
Are you looking for a backpack for just traveling or are you looking for one for travel and backpacking? Backpacking backpacks get pretty beat up when you check them for your flight, the carrosel can rip them up sometimes.
Here's my recomendations:
For a carry on travel backpack that you can still use for backpacking if you really want to get the Dana Design Far Flung. I just picked one up for $100 at moosejaw.com. Dana makes arguably the best packs in the world. This one can go carry on, has a removeable daypack and an integrated duffel bag it goes into when you want to check it at the airport to keep it safe from harm.
If you want a larger sized pack made specifically for travel they have the Swift Traveler. danadesign.com
Osprey makes a travel pack called the Departure which comes in different storage capacities. It's pretty unconventional looking too.
Now for Backpacking backpacks. You're pretty much stuck with top loaders 'cause that's just how they make most packs nowadays.
Dana Design Alpine: Can carry monster loads no problem.
Dana Design Bridger: Lighter suspension than the Alpine but you won't know it until you start packing more than 50 pounds (which is a lot)
Dana Design Bomb Pack: Similar to the Bridger but a bit smaller in capacity. Won't start sagging until you put 40-50 pounds in it.
Osprey Luna: Osprey packs are another top of the line backpack. They don't just have Womens sizes. They make packs specifically to fit a womans body. The Luna is the workhorse of their female line. http://www.ospreypacks.com/3D_Luna/luna_intro.htm
Osprey Ariel: The Ariel series cuts down the weight of the pack without compromizing it's load bearing capacity. A lighter pack is easier to carry. http://www.ospreypacks.com/ariel_intro.htm
ArcTeryx: Made in Canada, Expensive and worth it. Their Bora series ranges from 45 liter capacity all the way up to 92 liter. They are one of if not the best quality made pack available and completely bombproof. They are rugged and heavy though, more suited for mountaineering than travel, but you can drag these things behind a donkey thru the jungle without worrying about your clothes getting wet or hurting the pack. Some people just find their waistbelts too padded (if that makes any sense) and stiff .
The above packs I've listed for you are so well made and so comfortable to carry that I am confident buying any of them online for myself without trying them out first to see how they feel. Packs are like shoes though. And backpacks are best when fitted for you if you are inexperienced fitting packs on yourself (especially Osprey who sell their wide selection of waistbelts seperately in order to better customize each packs fit to your body type)
Another pack I like but needs to be tried on before laying down the money for it is the Mountainsmith Specter. I liked the pack a lot, it just fits me funky compared to Danas and Ospreys.
It's been discontinued so you might find some good clearance sales.
Mountainsmith mountainlight series: http://www.mountainsmith.com/store/?page=s...877a9a052ef8a16
Mountainsmith travel packs: I don't have any personal experience with their travel line so I can't realy say much about them. http://www.mountainsmith.com/store/?page=s...1b620cc5861ab57
Other packs that are good (but in my opinion not as good as the ones I've listed for you above) are:
Jansport (careful here. not all their packs are created equal. pioneers of the "lifetime warranty")
Here's some review links for ya:
Search for sales. Depending on your height (most Women fit small packs which are the hardest for retailers to sell) you can find some incredible bargains on some expensive packs. Also check Ebay regularly.
I hope this helps you some. If you have any other questions I'll try to answer them (I'm just new to 'travel' backpacking. I've been wilderness backpacking all my life.)