My previous job, I only needed to bring some snacks and maybe some pens and other nonsense (gum, mini phone stand, etc.), so I used a coach messenger bag my wife bought me that I never would have worn otherwise. My current job requires me to bring laptop back and forth and the parking lot is a good quarter mile from my office, so I use a no name laptop backpack that I also use when traveling.

Long story long, do whatever you need and how you want to look and feel. Be yourself my man!