My husband uses an old carry-on from Eagle Creek with wheels and optional backpack straps (which we never use) and I have a newer Delsey that I use a lot for business travel. They are both great, well made, lightweight bags. Regardless of what you buy, look for: weight & durability (even if you intend to "carry-on" all the way, it's not uncommon for an airline to make you check bags if the plane is full so light and flimsy is a bad combo), good inline skate type wheels (work quite well on cobblestones etc.), pull the handle out all the way and roll around the store (wobbly handle = bad), zip it open and look at the inside (a well-designed bag can hold more stuff than a poorly designed bag w/same dimensions). We both prefer messenger bags to backpacks for day bags. They are comfortable and look less touristy. LLBean makes a good one with a padded strap.