I've just come in on this thread so forgive me if I've repeated but I think if you don't feel content with what you have now, you never will be, bcoz you're looking for happiness in the wrong place.. I know rich people and I know poor people and the unhappiest of the lot are the ones that can't live without the luxury. I'm not talking about all the rich ones, I'm talking about the ones that can't live without the money and the ones chasing it. The ones that, if they lost it all tomorrow, they couldn't go back to a normal life, or those that work 17 hours a day so they can have a posh car and house they never see.
Most people I know who can't live without it are either the ones in debt, who don't really own the stuff, just have it on tic, or the ones who were so busy making the dollar, they forgot to live. In fact I know some who's jobs are well paid but so demanding, they don't even get to enjoy what they have, and they've lost their nearest and dearest bcoz they chose money over love, and that is what it usually comes down to. Not only do wives get fed up and go but money attracts shallow people, so you rarely find genuine friends who would stand by you if you went bankrupt (simply bcoz you no longer can afford their lifestyle)
If material things are really what you want though I would suggest a career change. Lawyer or accountant might get you these things. But in my opinion they won't make you happy bcoz you are backing the wrong horse.
And when you're really feeling hard done by, remember you are richer than about 80% of the world's population. It's not becoming content you should fear, it's the love of money you should fear as it this that will imprison you, take your freedom and cloud your judgement about what is really important in life