I try my hardest to keep this list short, because being a food snob is expensive, on top of being annoying. However, the list does grow year by year.
Whole wheat flour-- there is absolutely no comparison between the stuff you (usually) buy at the store and fresh-ground. Only lack of money, storage space, and willingness to loose my hearing keeps me from buying a wheat grinder at this very moment.
Lemon and lime juice-- almost nothing does not taste better with fresh juice. I do find, however, that the lemons or limes in question are much easier to squeeze efficiently when I let them sit long enough that their skins get thin. So, juice from a lemon which has recently been whole, but which is not, itself, fresh fresh. (Actually, truth be told, I tend to eat more limes than lemons. This is because they are cheaper, and after my Mexican roommate told me that they don't differentiate them, lingistically or culinarily, where she comes from, I decided that I didn't care either.)
Oatmeal-- no, I do not prefer fresh. I prefer organic. I started buying it a couple of years ago at The Good Earth (local health food store) because there, even the organic stuff costs less than what you would find in a regular grocery store, so I thought: why not? I ate this stuff for months and months. We have a running joke at my house about how if you looked in my ear, the stuff inside would be gray not because it is my brain, but because it is oatmeal. I often eat it every night. One night, when I ran out of the organic stuff and had to use my roommate's "regular," I discovered, to my chagrin, that I had developed yet another food snobbery. The regular stuff really does taste like cardboard, now. But I don't think I would know if I didn't eat it as often as I do.
Tomatoes-- these are hardly worth mentioning, since any human being who does not hate tomatoes and has normally functioning taste buds is perfectly capable of figuring out that store-bought tomatoes tend to be pink-to-red-colored solidish water, and home-grown are the real thing. The only thing to add is, my father grew some Juliets (it's a variety) in the garden one year, and I still fantasize about eating such delicious tomatoes again.
Butter-- OK, so first thing, I eat butter and not margarine. After all my talk about trying to save money, there is the plain and honest and naked truth. But I will say that I go through it VERY slowly, unless young relatives who are reckless with the butter knife have been visiting. The second part of this confession is that I buy the kind of butter which has a very high fat content. I mean, if I am going to buy fat, I want to buy fat. I can skimp on it in my own kitchen; why pay someone else to do it for me?
Honey-- this only makes sense, since my very own great-great uncle was the owner of Cox's Honey in Shelley, Idaho, and that means that the current owners are probably something like my third cousins once or twice removed. I have tried the Cox's Honeyland honey from Utah, and I must say that it just isn't the same.
Gotta go. More later, I hope.