Here are some brief notes on stores we visited. Most of these have to do with food or wine, as we tend not to buy souvenirs or designer goods.
An oddly-named "department store" on the very central via de Calzaiuoli, and not the sort of place we would ever go into, except that N accidentally brought a pair of my shorts along instead of her one pair of long pants which she wanted to take carry-on into the plane, so we had to buy something longer for her for the more strict churches. She spent way too much on a simple skirt with an elastic waistband, but it was our first day in Europe and none of us wanted to spend much time on the errand. There were cheaper wrap skirts (basically just a rectangle of cloth) which seemed less practical, and sure enough, walking across the Ponte alle Grazie later in the day, we saw someone fumbling with one and almost tripping over it.
The nearest supermarket we knew of was a ten-minute walk northeast (longer on the way back laden with stuff). Supermarkets are not choice destinations, but serve a useful function: they let us get things whose names we don't know, and they let us look at labels (of jams, yogurts, and juices) to check out ingredients. They also tend to be open for longer hours; on Sunday, when no other food stores were open, we managed to buy ourselves enough fixings for a decent dinner (cheese, bread, vegetables, salad, wine). Being in the centre of the city, this was a fairly small place, but with a good selection. They seem to have a reasonably-priced organic house label.
Recommended as a bakery; we tried to go and get breakfast stuff before a visit to the Ognissanti. The place is incredibly narrow, with a high glass counter, and a couple of nice elderly women behind the counter. Very little was labelled, or identifiable. We ended up with a couple of pane rosmarino (sweet flat rolls with raisins and dried rosemary), a small whole-wheat roll, and a sort of cornetto called "pologne" for some reason. Decent, but not worth the hassle.
This shop has a very nice selection of wines plus some other artisanal products, with prices clearly marked, and the single person in attendance left me alone until I was ready to pay. On my first visit, I went for more unusual offerings: a Sicilian Nero d'Avola (Primoquarto), a Rosato from Colli della Toscana centrale, a pale Vino Santo del Chianti Classico from Fattoria della Aiola, a small bottle of artisanal limoncello from Procida (for Z, who likes having tiny sips of the stuff), a small bottle of extra-virgin olive oil from Frantoio del Castello di Poppiano in Montespertoli, and the lowest (aged four years) of three grades of Aceto Balsamico di Modena from Azienda Agricola Aggazzotti dr. Pietro, which proclaims on the label that it does not contain E150 caramel colouring. On a later visit, I bought a half-bottle of Il Grigio di San Felice Chianti Classico Riserva, one of the few times I saw what looked like a decent wine in that size.
A small place recommended by the Miller book, with a friendly proprietor and high-quality products. We bought prosciutto toscano, bresaola, a nice mild goat cheese (caprino), and pecorino di Pienza. Just down from Vini e Olio on via de Serragli.
A spontaneous pastry stop in the Piazza della Republica on the way to our train to Pisa. A and Z had a bomboloni (doughnut) filled with Nutella. A said afterwards, "I shouldn't have had it, but it was good." Z was a complete mess. N and I had good pain aux raisins (I have no idea what these are called in Italian) and I had a decent espresso. The staff were friendly and the atmosphere pleasant, and there were stools opposite the banco on which the kids could perch, so we returned a couple of times, trying a few more pastries (I remember brioche di mele and brioche con crema). A cappuccino had nice "latte art" but was a bit tepid, though a sip inspired A to ask for her own, so on our next trip, she had her own macchiato, the first time she's ever had a whole coffee to herself.
Fancy-looking shop; I waited with the kids outside, while N went in to locate Mattei biscotti, which we'd had fresh from their shop in Prato on our previous visit. She found a bag, which turned out to be 9.80, and (when we checked the label) baked in March. They still tasted good, and the kids really liked them dipped in Vin Santo.
Way out on Piazza Beccaria, which turned out to be mostly under construction. The shop was tiny, and had a small selection of five different kinds of tarts, plus some larger ones in the window. That was about it. We bought four, at 3 euros each; they were good, but not exceptional. The famous chocolate torte turned out to be mostly solid ganache, not very sweet, but not that subtle, either. If this is the best that Florence has to offer, it can't compete with most decent-sized French towns.
A nice kitchen store -- we kept finding new niches. The kids were impressed with the Alessi display, and then found four bunny popsicle-makers (a knockoff of an Alessi design that was 23 euros) for 1.90. We bought them.
In the Mercato Centrale; a bit touristy (lots of signs and samples), but a good selection. I bought salume di cinghiale, prosciutto Cina Senese, and pecorino mezzo-stagionato, all of which were great (the salume was a bit hard to cut, but really good, better than I thought it would be, and it lasted through several meals, as it was quite rich and flavourful).
A nice wine shop recommended by the Miller book. On their advice, I bought a Rosso di Montalcino from Casanova di Neri and a Chianti Classico 2002 from Querciabella (the former good, the latter excellent). I also picked out a Moscato di Pantelleria from Isola di Vento, which had a very nice perfume and made a nice ending to several meals. We went back for Mattei biscotti, only 6.90 here, and baked quite recently (though not as recently as the ones we'd had from the Mattei shop in Prato on our first visit to Toscana).
This was a crowded, dark bakery on a back street behind the Coin department store that I wouldn't have given a second glance to, but for the Miller book. We went there a couple of times for potato and onion pizza (sold by weight, and often the leftovers were polished off by the kids for breakfast), and bread.
Another place I wouldn't have looked at, with fancy displays of candy facing onto heavily-travelled via de Calzaiuoli, but it came recommended. The kids had never had marzipan (mazzapane), and were taken by the look of it shaped into little coloured fruits, even though we warned them they would all taste the same. A little bag of ten (each one a little more than two centimeters in diameter) cost 3.90.
A bit pricier due to its location just behind the Palazzo Vecchio; their prosciutto Cinta Senese was 99 euros a kilo. But the products appeared to be of high quality. I bought pecorino stagionato latte crudo (made from raw milk), quite dry and quite a hit with everyone, and prosciutto toscano sotto cenere (covered in ash to age), which formed part of our lunch on the train to Venice.
I hadn't brought the part of the Willinger book which talked about this store, at which we had bought organic green lentils on our previous visit, but in trying to locate a restaurant for lunch, we happened to pass right in front of it. I have other sources for lentils now, but I bought a kilo and a half of farro, which I can't find easily at home.
A nice looking bakery with a narrow and picturesque room beside it for wine tasting and snacks. I went in to try locally-roasted coffee, as always less than a euro at the banco. The young barista had his hair moussed so it went up in five-centimetre spikes. When I got my coffee, the kids wanted a sip. A took one and flinched at the heat, which made the barista snort, but when Z (more used to having sips of mine) sipped and nodded vigourously, he broke out into a big grin. The kids also noticed a flat cookie called cialde de mandorla, very thin and embossed with a design (almost like pizelle), with a crunchy almond filling; it was quite tasty.
Nothing much to distinguish this place from the other snack joints lining the Piazza San Marco, which is one of the main city bus hubs, but according to the Miller book, this is the best schiaciatta in town. I don't know if it is that, but it was the best we had, both plain (with oil and salt) and in onion- and potato-topped versions (which came with us on the train to Venice).
We made several trips to this pastry shop north of Santa Croce; it was fairly convenient and quite good. The kids enjoyed their bomboloni (crema, cioccolato) and cream puffs; N and I liked a custard cookie that was like a mini torta della nonna and a good sfogliatelle (not too rich or sweet). Their zuccotto was a bit of a puzzle, as it didn't have any ricotta, but seemed to have vanilla ice-cream and chocolate whipped cream. We bought some of their freshly-made biscotti to take on the train.