I've never been one to be organised enough to do a shopping list! DH and I do the grocery shopping together and have a 30min drive to get there, so we discuss what we want for dinners on the way there and buy what we need for those. If regular things we use are on special we also buy those regardless of whether we actually need it that week. We plan for 6 meals for the week because we know one night we will either have take away/go out or just make do with whatever we find in the house.
I would like to be a bit more organised, but it never happens! DH also usually ends up back at the supermarket a day or two later to get a few things we forgot!