Jeb Bush, followed by George P. Bush.
Gekko, I'm talking about a hypothetical in order to make the point that there is a level of deaths you cannot write off as "just the casualties of war". The salient fact here, though, is that few or none of those ACTUAL casualties (100k dead Iraqi civilians) would have happened if Bush hadn't decided to PNAC up the Middle East. If it were a situation like, say, Israel/Palestine, which is a genuine war, I would view accidental civilian casualties on a different level. But Bush's war is not even close, and its casualties do not deserved to be minimized in the same fashion.
The only problem with the Hitler comparison is that people tend to remember the "genocide" component of Hitler more than all the other bad things, and I don't really think Bush is heading toward genocide.
When Bush is compared to Hitler in the future, I would look at Hitler's insane nationalism and pride, his expansionist militarism, and his willingness to warp the facts and step on treaties in order to export his ideology to the rest of the German nation and even to others in the world (Vichy French, Palestinian, Bosnian Muslims, etc). There you will, in four years, find some accurate comparisons with Bush.