From a March 2008 Guardian Article on exactly this controversy (meaning Lancet vs. IBC vs. ORB vs. WHOI et. al.):
"The controversy will clearly run and run, probably long after the Iraq war eventually ends. One thing is certain, and it provides no comfort for Bush, Blair and other occupation supporters. They continue to claim that, whatever errors may have been committed since the invasion, the judgment of history will be that the toppling of a brutal dictatorship was an unmitigated benefit. That alone means the invasion was a blessing for the people of Iraq.
Alas for Bush and Blair, most statisticians do not support their case. Nor can any journalist or other independent witness who has seen the pain of the bereaved still living in post-invasion Iraq or the millions who have escaped to Jordan and Syria. Estimates of the Iraqi deaths caused by Saddam's regime amount to a maximum of one million over a 35-year period (100,000 Kurds in the Anfal campaign in the 1980s; 400,000 in the war against Iran; 100,000 Shias in the suppressed uprising of 1991; and an unknown number executed in his prisons and torture chambers). Averaged over his time in power, the annual rate does not exceed 29,000.
Only the conservatively calculated Iraq Body Count death toll credits the occupation with an average annual rate that is less than that - some 18,000 deaths in the five years so far. Every other source, from the WHO to the surveys of Iraqi households, puts the average well above the Saddam-era figure. Those who claim Saddam's toppling made life safer for Iraqis have a lot of explaining to do."
full article with discussion of the merits and flaws of the various counts is here
a lot of 'splainin' to do.....