While I'm sure there are people who buy just to look good (and they're the people we love to hate), I think plenty of us just want to have certain things which match with our interests.
I love watching movies in the evening with my wife, so we have a nice big 60" HD plasma. It certainly was a big consumption, but it has been a great value for us.
I like books, I enjoy holding them, I like their smell, and I enjoy sitting in a room with books surrounding me, they give me warm fuzzy feelings. So I spend a lot on them. Amazon thinks I'm a wonderful friend.
My wife and I are tech people, we have around 7.5 computers in the house (a few are in parts, I figure that's about what they add up to). Most of them are older, but we're generally pretty good about keeping upgraded. It's expensive, but it's certainly something we use a lot.
Anyway, I don't view them as conspicuous as it was explained in the past messages, as I don't care what people think about my computers, my TV, my books, etc. They're just things I like. I have the money, so I buy them.
My wife doesn't like jewelry, she has her wedding ring and that's it (doesn't own any earrings, necklaces, etc). I don't need fancy bikes, new cars, etc. It's all about priorities. Some people don't have interests which cost money, or they don't have the money to purchase them without it being a "large" impact.