I generally only plan one day in advance, unless we have visitors then I have it down to a tee.
I too tend to get the packs of meat and then do enough for 4 and put half in the freezer so if I can't be *rsed then I know I have something I can eat.
I usually have a rough plan (ie for the week ahead I know roughly what seven dinners I'll be making) but I don't decide what I'm making until the night before.
On a Thursday or Friday I'll check what's in the freezer from my big monthly online shop (meat/fish etc) then work out Bfast, lunch and dinner around it for the following 7 days.
I then write my shopping list around this and buy what I need on a Saturday.
I do this for both convinience and money - I don't really get much opportunity to shop midweek so if I haven't got something in I tend to have to wait until the weekend for it.
Most of my weekly shops tends to consist of loads and loads of fruit and veg