beardedbruce, from the website I posted a link to earlier, on the subject of Iraq Body Count...

"When President Bush recently spoke of 30,000 civilians killed in Iraq, his press secretary said that he was citing 'published reports.' Directly or indirectly, what he was probably citing was Iraq Body Count. But I Iraq Body Count's database is not intended as an estimate of total deaths. Its methodology is to record only war-related violent deaths that are reported by at least two approved international media sources. This generates a record of deaths that is accepted by the media that publish these reports in the first place. Its authors acknowledge that thousands of deaths go unreported in their database, but they say they cannot prevent politicians and the media misrepresenting their figures as an actual estimate of deaths. Iraq Body Count's 'minimum' number now stands at about 34,000."

So since the Lancet study is the only scientific study that was disigned to measure the total number of civilian deaths, and since their methodology was the same as what was used to determine the number of civilian deaths in the Balkans war, I think we can probably say that theirs is the most reliable.