As a fiscal conservative, I've enjoyed a number of arguments with more liberal-leaning friends, and the word "fair" comes up too often when talking about wealth distribution. There's a fundamental misconception that money is taken. Let me clear this up:
The money you have is an IOU from Society.
If you are rich, it's because other members of society have given you their wealth in exchange for something you gave them. Money is another form of social value. When you generate value for others, they give you money. When you want value from society, you pay money. Here's the beautiful part: You give less money than the value you receive when you buy something (or else you wouldn't purchase) and you gain more money than the value you assign to the work you sell (or else you wouldn't do the work.) In this system, everyone wins. Social value is created where there was none before.
Unfortunately, when you create a very large amount of value for society, people who have not created value start to accuse you of theft. Theft is when you take more value than you create, or mooch off of someone else's value. Ironically, this is usually how these accusers acquire their wealth. I believe these people should be ignored and given zero consideration, as they keep you from helping greater society.
One thing to note: societal values are not the same as personal values. You may really love small painted coins, but if the members of society loves them less than you, they'll pay you less than you feel they are worth. That is not the fault of society, it is the fault of the individual. When you make or do things that people want, they'll support you and you can support them back.
Capitalism is a win-win system, and people who are wealthy from legitimate value creation should be honored, not attacked.
[Update from 2012: While in the grand scheme I haven't changed my views here, there are a number of caveats. The economy, like all complex systems, is nuanced and subject to manipulation by those in power. I'm far more liberal than I used to be.]