It appears as though Congress will not make any decisions on the tax code until after the elections are over. That means that estates created in 2010 will be using the carryover basis for larger estates. If a spouse is the surviving heir of the estate, an extra 3 K can be added to the assets. Otherwise, the basis of the assets will be $1.3 Million. Due to the threat of lawsuits, retroactive reinstatement of the estate tax would be challenged in court.
The rest of us can almost count on at least some retroactive tax changes--we can't afford the big bucks to challenge in court.