Like Chrisbee we generally use the nearest - but our preference if there was a choice would be HyperU - which we think is the cleanest looking (especially the new ones), and generally has a good choice and range of products. Where we are now there's a HyperU and just nearby a Lidl, so we've been doing a 'joint' shop - Lidl first, and anything we can't get there, or don't fancy, we'll get from the HyperU or even from our campsite shop (a 'Utile' - which is the local version of the 'U' supermarkets, and offers their 'value' products). Then we use the little shops in towns and villages for breads, pastries, quiches, tart(e)s etc. and did a lovely shop in Les Halles in Narbonne, but sadly that cost us an arm and a leg, and in the end wasn't really any better than the supermarket produce - sad as that sounds. I used to love markets, but at this time of year, when there aren't too many buyers around, some produce, particularly fruit and veg, is sometimes looking as it if might have been out in the sun for too long - so we've stuck to the supermarket for fruit and vegetables - though we did buy some very nice apricots and strawberries today from a local grower (unfortunately all in poly-tunnels!!!!!)
We had a Lidl chicken yesterday, which cost just 3 euros 59 cents, a 'Poulet Jaune' (or corn fed out door chicken) and it was absolutely delicious. We also had some crevettes (prawns in shells) from the HyperU, last week, which during the week are 5.95 a kilo, but at the weekend rose to 11.95 - we'll wait until they come down again before buying some more. Tip - suggest you try shopping mid-week, and avoid the weekends, and we've notices prices seem to rise.
Fuel here at the HyperU, today, is 1.337 for diesel (didn't notice unleaded price, sorry) which at an exchange rate of 1.25 to the £ is a much better deal than last year!