Depends on what I'm buying I guess. Aspirin, cough syrup, things like that I'll buy generic. Deoderant, shampoo, toilet paper etc... brand name.
Paper towels, again whatever is the cheapest.
As far as food goes, flour, sugar, I go for whatever is cheapest. Canned goods, cereal, soups, always a name brand because believe it or not I can tell the difference.