There is a reason that Outside Magazine named the Osprey Meridian 22 their luggage of the year in 2006. This is simply the best wheeled travel backpack on the market. I looked at packs from EMS, REI, High Sierra, Eagle Creek, and The North Face, and the Osprey pack had the best combination of features and storage space by far.

I started my search looking for a carry-on legal travel backpack with a removable day-pack. The problem is that most carry on packs have tiny main compartments, some under 1,800 cubic inches. Others have more room, but offer little in terms of travel security. This bag is a whopper that is carry-on legal with 3700 cubic inches of space in the main bag. This is also the most comfortable of all the wheeled travel bags I tried on, and only the Eagle Creek bags came close in comfort for non wheeled bags.
As far as security, both the daypack and the main bag have no easy access external zippers. So prying fingers can't steal your stuff while this is on your back while travelling. In fact, the day pack has one of the most clever ways of opening of any of the daypacks I've seen.
If you're looking for a lightweight, super well made, smartly designed wheeled travel pack that is carry-on legal, this pack is your only choice! 5 stars