Just as you would not allow a child to play with matches, you should never, never, ever allow Congress to play with the tax laws.
Playing with taxes is too tempting to them. Congress (and to be fair the President) see taxes as an easy way to manipulate policy. NO! Nor are taxes a way to look good in an election year. Taxes should be to raise money for the government to run. After all the last minute extenders, AMT mess and the "fixes" to the tax code that actually cause more problems, Congress should be allowed to vote on tax bills created by the Treasury and the IRS. No sticking in some one year special deduction into a tax bill and no sticking a tax clause into another bill to hide it. If Congress doesn't like what Treasury proposes, then they can defeat it and let them draft another one based on Congressional input.
Right now, the Congressional moths are focused on another financial flame, the credit crisis. But they still have a tax extender/AMT bill to finish soon and that looks to be in big trouble. The IRS needs time send forms to the the printer and re-program computers but they can't do that until Congress does it's job. But Congress is more interested in playing with taxes to look good to their voters than to solving the problems they are causing.