(MONEY Magazine) – The Republican takeover of Congress virtually ensures a slew of tax cuts that could take effect, retroactively, as early as Jan. 1, say tax experts and Washington insiders.

Proposals most likely to garner widespread bipartisan support include lowering the top four income tax rates in 2003 instead of 2006; increasing the per-child tax credit from $600 to $1,000; and boosting contribution limits for 401(k)s to $15,000 a year and for IRAs to $5,000.

Increasing the amount of income that's taxed at the lowest rate (10%)--similar to the move that resulted in those rebate checks in 2000--is also likely to pass, as is a proposal to increase the amount of investment losses you can deduct per year, from $3,000 to $8,250.

More contentious is the move to make all the cuts permanent after 2010, because built into the proposal is an effective repeal of estate taxes. But even on this the GOP is thought to have a good shot at enough support to override a Senate filibuster. After all, says Bill Gale of the liberal Brookings Institution, "the Democrats voted for the 2001 tax cut, and a lot of them will vote for a cut again." --LESLIE HAGGIN GEARY