I prefer plastic. This way I can carry eight bags in at a time. Most of the time, thats one trip for me, one of the kids get the bag(s) with bread or chips.
Glass or plastic isnt a big issue for me, cans are. I hate cans. If its a drink in a can, I'm not gonna drink it because of the aluminum aftertaste. It turns my stomach. I think its where I worked for OMC, aluminum doesn't have a very pleasant smell when its being machined, brushed, or polished, and after having to smell it for 48 to 60 hours a week for a year you get sick of it.