I combine the two these days.
I'll very often window shop for clothes and try things on, and then if I still want it, buy it online later (stops so many impulse buys or I'll see if I can catch the same item later online in the sale). So the store has a purpose, but I don't always buy at store.
I have bought clothes online alone, but more often than not its a great big fat waste of time and takes more time and effort to return stuff.
The exception being bras where I simply have NEVER been able to find anything in my size to fit, so have always used online (Bravissimo stores started opening up after I had problems and I still have issues with the stuff they often stock. Not to mention actually going to a store tends to be a great big trek. And stupidly overpriced).
I tend to try and avoid using the main supermarkets when I can. I refuse to get a loyalty card of any type. I try and buy seasonal produce as its fresher and tends to be more likely to be British grown. I tend to go shopping when I have to do other things to avoid extra miles on the car and the cost of fuel, so that largely dictates where I end up.
The cost of fuel has had a big impact on where we shop tbh. We don't do it as much as we used to. Likewise, we do tend to go places where parking is free (or Sunday shop as again, its free).
I don't buy supermarket fuel as for some reason my MPG goes down quite a bit when I do, so Shell, BP, Total etc actually seem to work out better value if I can get it at only 1p a litre more.
I try and use specialist music shops where I can. It tends to involve a special trip but its worth it. I still buy the occasional bit of vinyl too.
I try and buy direct if I can for most stuff I buy online. For example buying travel guides from Lonely Planet not through a third party like Amazon. DH tries to get his good outdoor equipment stuff from brands that are ethically motivated or British based as much as he can (He loves Alpkit). For the bits and pieces he goes to Decathlon, so he can save his pennies for more important kits of kit.
I actually browse Amazon a lot, and then source stuff elsewhere after comparing stuff.
We do use Amazon, but we do try and keep it to a minimum if we can. Over the last couple of years the selection of books has gone down a lot. We used to have a very good Borders nearby, but since that closed, we've had to use Amazon more.
Big purchases such as camera or computer we've recently done through John Lewis because of the better warrantees and service you can get than buying direct (Apple needs to step its game up on this one, as its lacking).
I refuse to get a kindle and I don't buy MP3s.
I'm very conscious of spending pounds wisely, and efficiently rather than picking the cheapest as I don't think it works out cheaper in the long run, if it puts people in the UK out of work. It all comes back round in tax or cuts or an increased unemployment benefit bill, so you don't win in the long run. It still costs you, further down the line. If I can buy British or British made I will. But equally I still refuse to pay a huge premium to do this. I do believe there are a lot of business models that do work in the face of the supermarket giants and likes of Amazon and don't cost the earth.
Oh, and I don't use Starbucks. But thats mainly cos I don't like coffee or tea and its hideously overpriced anyway.