After trying a few types I've stuck with one version of the Eagle Creek Pack-It Slim Kit like this one though mine doesn't have the single zippered center pocket but several smaller open pockets instead. I like the new design better but decided it's just not worth the $20-odd dollars to me to upgrade my toiletry bag.

Overall it works well as it hangs on the towel hooks in most hotels, cruise ship cabins and is fairly light and can pack flat enough if you find the best way to arrange the items.