Honestly? Longchamp Le Pilage in size large. I often use my Totally MM also but prefer Longchamp because I can set them on scuzzy floors of planes and bathrooms and clean them up with soap and water or wipes. I usually bring a few because they fold up so small and flat. They make great beach bags too! I'm actually in Cabo right now and have three with me!
I always bring my Neverfull GM whenever I travel.
Should I use my Metis hobo? Will that be too flashy?