Since the U.S.-led invasion in March 2003, more than 15,000 American service members have been wounded in the conflict, according to the Defense Department. According to CNN's tally, 2,194 coalition troops have died in the war.
The number of civilians killed in Iraq in war related incidents since the Iraq War began is estimated at from 26,690 to 30,051. These civilian casulties include (via Wikipedia):
Many non-combatants from both coalition and non-coalition countries have also been killed or wounded, including more than 40 journalists and more than 150 international aid personnel and foreign civilians.
Some of the 18-20,000 contractors and armed guards in Iraq, many of them working for the U.S. Department of Defense, have also died. As of October 9, 2005, some 273 foreign contractors are known to have been killed. These include security contractors, truck drivers, construction workers, and businessmen. The contractors came from the USA, European coalition members, and non coalition countries like South Africa and Germany. However, the nation with the largest number of contractor deaths is the United States, with at least 105 killed.
The breakdown of order in Iraq that has followed the U.S. led invasion and occupation of the country has also resulted in an increased rate of not clearly political criminal homicides in Iraq (via the Wikipedia link above):
In 2004, the Associated Press completed a survey  of the morgues in Baghdad and surrounding provinces, to tally violent deaths since President Bush declared an end to major combat operations. In Baghdad alone, they counted 4,279 such deaths in a city of 5.6 million; these deaths generally do not include combatants, because they are typically not brought to morgues. This death rate translates to 76 killings per 100,000 people, compared to 39 in crime-ridden Bogotá, Colombia, 7.5 in New York City, 3.0 in Baghdad itself in 2002 (the year before the war), and the international average rate of 5.5.
Morgues surveyed in other parts of Iraq also reported large increases in the homicide rate. For example, the rate in the province of Karbala, south of Baghdad, rose from an average of one homicide per month in 2002 to an average of 55 per month in the year following the invasion; in Tikrit, north of Baghdad, where there were no homicides in 2002, the rate had grown to an average of 17 per month; in the northern province of Kirkuk, the rate had increased from 3 per month in 2002 to 34 per month in the survey period.
Estimates of the number of Iraqi military casulties during major combat operations (the 6 weeks of "major combat" in March–April 2003) during the Iraq War varies significantly (via Wikipedia):
30,000 (estimate by General Tommy Franks)
6,119 to 15,925 (from a compilation of incident reports)
4,895 to 6,370 (one study's estimate)
13,500 to 45,000 (one journalist's estimate)
The number of Iraqi soldiers and police allied with the U.S. led coalition in Iraq is estimated (also via the same Wikipedia entry) at:
Iraqi allied soldiers: number unknown. At least 2,180.
750 Iraqi policemen (according to a senior US official as of 6 October 2004
The number of Iraqi insurgents (likely not all part of a single organization) killed to date in the conflict is not known with any accuracy. It is safe to assume from various new reports of battles with insurgents, in which the insurgents very frequently suffer more casualties than the U.S. troops whom they target, that this number is, at least, in the thousands, if not the tens of thousands.
The number of people who are not coalition military personnel who have been wounded in this conflict is not known. It very likely greatly exceeds the number killed.
My conservative estimate, based on the information above, is that the total number of people who have died as a result, directly, or indirectly but clearly as a result of the conflict, exceeds 48,000. My conservative estimate of the total number of people seriously wounded in this conflict is that it exceeds 100,000. I believe that it is appropriate to consider, when weighing the cost of the Iraq War, not only U.S. military casualties, but the number of dead and wounded from all parties combined in this conflict.