Hi! I was just walking through the new Macy's store in downtown Minneapolis (which replaced our beloved Marshall Field's) and I realized that we have a brand new (well, new to me) LV boutique! I'd like to make my first LV purchase - a keepall bag. But I'm having a hard time deciding which size is best - what do you have and what do you like? I'd be mostly using it as a carryon, and I'd like it to fit underneath the seat in front of me instead of in the overhead compartment. Thanks in advance for your advice.