I prefer a vest to a chest pack, its just more comfortable to me. That said I prefer minimalist whenever possible. I use a lanyard with a small homemade fly box (a Sucrets box with a business card magnet glued to the lid for nymphs) and usually a waist pack with it. I sometimes wear the waist pack as a sling pack.
The Sucrets box also holds an extra leader, indicators, and some split shot. In addition to the box, the lanyard holds tippet, nippers, forceps, frogs fanny, and has foam for dry flies.
I don't like a lot of stuff weighing me down and the more room for stuff you have the more you'll carry.
When brookie fishing a small stream I usually just use the lanyard.