I feel like the GST is just as classic as a jumbo, but I'm also partial to the GST as that is going to be my first bag. I like the classic flap bags, but in the smaller sizes, but that is just my opinion, I still think the jumbos look nice, it's just not my preference.
This is going to sound simplistic, but when I'm truly having trouble deciding between two things, I flip a coin and my true feelings come out - either I'm sad about the coin toss result or I'm happy and I quickly figure out which thing I want more. Sounds weird, but it always works!