While I use trunk bags and like them, one downside is that most are not made for quick on-and-off, as they require 2-4 velcro straps to be threaded around your rack. Panniers are much quicker to take on and off the bike, and generally easier to carry. One front pannier carried on the rear rack is what I use for commuting to carry lunch and some extra clothes. They are pricier, but if you might eventually need panniers for touring, you might consider using them for commuting also. Just another option to consider.