Most important to me is if it will hold everything I need to carry without looking either empty or overstuffed. I'm not much on organization, more of a 'throw it all in and dig' person so if it has too many pockets it doesn't appeal to me. Weight is important too as I have back and shoulder problems. I usually go for coated canvas but if I do buy a leather bag it has to be lightweight. Style as well - I prefer handheld bags rather than shoulder or crossbody. Designer or not, or particular designer isn't that important to me, but it has to be worth the money (excellent quality if it's an expensive one, or even if it's a cheap Walmart bag it can't have any snagged threads or whatever).