All plays a part.
After owning and owned 20+ bags of all types over the years, I can say, safest bet is a roller bag for the bigger projects, followed by a haversack for 2 bodies, 2 flashes 3 lenses setup, with laptop capacity, and a small shoulder bag for short events where you need to move fast, the 1 body type of setup. Even better if this shoulder bag enable you to stack with the roller bag. With this three bags, you are ready for everything and decision making is fast.
WTB Manfrotto RC4 L Bracket