"Fair" Taxation

Everybody want taxes to be fair.  Everyone should pay their fair share.  The Prez says, "I want the rich to pay their fair share."  Who doesn't want to be fair?  We have been taught from a very young age to "Play fair."

But, what is fair?

1. Everyone pays the same amount of tax?  That is, lets say everyone pays $150 - no matter what.  We are all citizens, so maybe we should all pay the same.  That sounds fair.
2. Everyone pays the same percentage in tax?  That is, I make $1000 and I pay $100 in taxes.  You make $2000, you pay $200 in taxes.  The more you make, the more you pay... It's only fair.
3. Everyone pays a higher percentage the higher their income.  That is, I make $1000 and I pay $100 in taxes.  You make $2000 and you pay $300 in taxes.  The more you make, the more "extra" money you have laying around, so you can afford to pay even more.  

Each of these could be construed as fair.  But, they are mutually exclusive.  You can only pick one.

Which one is "fair" to you?