I will comment lightly on this as some luxury items have an allure that may transcend ego.
For example I like good cloths and accessories such as watches and I-pods. Now I don't drive or own a car as some of you already know, regardless I would still love to own a 2007 Mustang or a Buell Street Fighter motorcycle. Do I need those items? No of course not, but would I like to own them, sure!
For those who purchase these items to make up for feelings of inadequacy or to make up for a lack of skill with their inner game then yes, such items only serve to give away the persons motivation for the ownership of said products. Those people who feel the need to justify or parade their value via material possessions are living a fake life.
I remember once vividly while I was tending bar in my youth a guy came in and eventually became a regular for about 3 months. Every weekend he would drive up in his porsche and bring a dupont registry magazine in with him to read while he was drinking. My job as a bartender was to promote conversation. So I get him and this girl talking, I walk away and come back to hear him talking about how he dislikes his porsche and is looking at Italian made cars. He went on about his house, his television etc etc. Very shameless and transparent.
To make a long story short the girl ended up going home with this broke ass musician that was preforming that night. This guy was barely kept, strung out tired and driving himself and his equipment around in a beat up van from the 70s. He had a game, confidence and allure that manifested to his inner worth. Meanwhile Mr. Moneybags was left holding a luke warm beer trying to make himself valuable to anyone who would listen by the objects he owned.
A car, house, income, jewelry etc etc....can all be taken from you at any moment in life. Your own personal worth and value you place on yourself as a man can never be taken from you. But it must be nurtured and developed.
Indulging yourself is fine and normal, its when greed and low self esteem drive these motivations that you become "the douche in the Hum V"