Many airlines will only allow one carry-on. With that in mind, I do use a tote bag for my carry-on. It holds just what I need (and more), is waterproof, has internal zippered pockets, has straps that can be adjusted (in case I want to wear it cross-body), and, most importantly, has a zipper (I secure it with a safety pin). If a tote does not have a zipper, it is begging dishonest people to put their hands inside and help themselves.... Oh, and it also spills when put on the conveyor belt at security checkpoints, in the overhead bin, or under the seat. You can find totes in many, many stores. I got mine online at eBags.
Have a great trip!