This isn't as much a tax raise as it is a repealing of the Bush tax cuts. Taxes will go back to what they were during the Clinton era.
This is
mostly true. Obama has actually proposed extending the Bush tax rate cuts except for the highest tax bracket in which he will let the rate sunset to what it was before. Again, only those that make over $250K will be affected (from an income tax standpoint).
Also, while not as fiscally conservative under the 2001 EGTRRA, Obama has proposed an estate tax plan that will essentially be much lower than under Clinton and will affect a much, much lower percentage of people as well.
Really, what this all these taxes boil down to is a "fairness" argument. The government must operate in an economic neutrality world. This means, in order to fund certain policies it must cut others by an equal amount (operating under a 10 year span). For taxpayers in the lowest tax brackets to benefit more, taxpayers in the highest tax bracket will help fund it. All this does is slightly raise the progressivity of the current tax system.
Everyone that argues for a flat tax, or a fair tax, or whatever tax you want to come up with, the government
has to be funded, overall, by the same amount in order to stay economically neutral. Congress does not want, or allow, the government to grow or shrink, from a funding standpoint as a whole. So yeah, maybe there are programs out there in which you pay less income taxes, but all that means is the government will get you from another angle, i.e, higher sales taxes, VAT taxes, state taxes, transfer taxes, etc.
Again, financially, the fundamental differences between republicans and democrats is the progressivity of the tax system. Who should pay for the government to run? Everyone equally? Or those who could "afford" it? This is an opinion question and is why we select our representatives to Congress and the Presidency to make this decision for us.