Everything except a very small number of products. eg. The store brand equivalents of total cereal are cheaper because theyre not as fortified. That is important for people that actually want that extra nutrition eg. women, people with anemia, vegans, anyone that drinks a significant amount of alcohol etc. Ranch used to be one of the things that I regretted getting the store brand (the store brand was NASTY) but luckily that hasnt been true for a while. Most medicines are just fine as generics as well and the ones that arent will generally be specifically requested by your doctor.