What kind of hiking backpack should I get?

It really depends on what you intend to use the pack for too. From the sounds of it you're not planning to hike through trails or be out in bad weather - in other words you're not going to need all the bells & whistles of a really technical backpack. If you're mostly interested in storing you personal belonging then you may want to consider an ultralight weight backpack with basic features, that way you aren't carrying a heavy pack with features you will never need.  Gossamer Gear makes a line of ultralight backpacks that have enough basic features for what you need and are sized to fit all sizes. [http://gossamergear.com/packs/backpacks.html%5D If you concerned about the thickness (strength) of ultralight backpacks, check out Gossamer Gear's Gorilla backpack [http://gossamergear.com/packs/backpacks/gorilla-ultralight-backpack.html%5D. It's incredibly light weight but also very strong.  Just an idea, less weight might help you in the long run.  Good luck with your search and let us know what you choose and why.

Keep it to about 50 liters or you might get flagged to check the bag. Gregory makes really good stuff. I like Osprey too but I find they use slightly less durable materials (with the plus side being they are lighter). I've read a few places where people use the Gregory Z55 bag and have been able to carry it on about 90% of the time. With your height.. that pack will look small on you and I'm sure they won't tell you it needs to be checked. I'd search and maybe ask this question on http://www.bootsnall.com/ and you will get plenty of info.