I think you guys are being a little general. Up until about 1800, it was possible in most wars for individuals to make money from them: kings would get territories to tax, soldiers and sailors would get plunder, etc.. But since the emergence of the modern state, it's the state that gets the booty - if there is any. Modern wars are so destructive that there is rarely much in the way of booty to collect.
It reminds me of the ridiculous marxist argument that Kosovo was about some mineral deposit. Don't be absurd; any capitalists interested in such a deposit could have bought it for less than the instability and risk of war might have cost them.
Certainly access to wealth might be a cause of war, or an excuse for it. It certainly was a major issue when the U.S. entered the First World War in 1917, angry that it could not trade across the Atlantic in safety. But the idea that "money" itself is the cause because people are hoping to "make money" in the same way as privateers did in the 1770s is just plain wrong.
I will vote "other," because the missing category is the obvious one: POWER. Politicians are the ones who start wars in today's world, for good or for ill, and even guerrillas and terrorists like Osama Bin Laden, Che Guevera and Savimbi were politicians first and foremost. Politicians deal in the currency of power, not of money.
Ask most (not all, but most) businessmen at any time in the past 100 years if they want a war of any sort, and the answer would be no; most are willing to take a hit to even avoid TRADE wars, since they are terrified at the chaos and risk to their investments that political events can create.
R.III