kewtogetin has more or less summed up my food snob specifics. I often buy value brands, but also get a lot of Aldi 'Specialy Selected' versions, which I think are often at least as good as Waitrose/M&S. I generally only avoid value brands for things like meat, where the meat content might be low, poor quality or low welfare.
However, I'm not snobby about brands and actually prefer Branston beans to Heinz. I don't think Heinz is actually a high quality brand - Baxters do better soup for example.
For lots of things, for me it's either Aldi, unbranded unprocessed or 'whatever brand is on offer' for things like toilet rolls or tea (for some unknown reason I haven't brought myself to try Aldi tea yet, despite buying almost everything else there).
Has anyone seen the 'Eat Well for Less' series that started last week. One thing I'm convinced of is that a lot of people wouldn't be able to pick out 'their' brand in genuine blind tasting, or may prefer the cheaper brand, if they could get past the 'it has to be Heinz' mentality. Or if you said Brand X is 50 pence an item but Brand Y is 1.50 an item, do you really think Brand Y is worth paying three times as much for, most people would be happy with the cheaper item to save money.
The programme more or less went along with this theory - the producers 'white labelled' a lot of the families shopping and swapped some and kept some the same. The man was convinced that the 'new' jam was cheaper and nastier than his normal brand when in fact it was exactly the same.
They swapped the families normal low quality but big brand Richmond sausages for naice butchers sausages that were only a tiny bit more expensive and unsuprisingly they liked them. They also liked Aldi ketchup, which is a lot cheaper than Heinz.