Also pinching themselves last week: the heirs of all the mega millionaires — and the five billionaires — who've kicked the bucket in calendar 2010, the first year since 1916 without a federal estate tax in effect. Those heirs had been keeping their fingers crossed, hoping that Congress would not vote to restore the estate tax retroactively for 2010. The tax cut deal announced last week includes no restoration. The deal, the Wall Street Journal reports, actually makes 2010 even sweeter for wealthy heirs. Some of these heirs face a capital gains tax on the profits they make from selling the stock they inherited in 2010. The new tax deal gives heirs the choice of either paying that capital gains tax or having the 2010 estate of their dear departed taxed at the much-reduced estate tax rate the tax cut deal puts in effect for 2011, whichever ends up costing the heirs less . . .