While all of the reasons that the Bush administration has given for invading Iraq have all been sounds reasonms for action, most people keep forgetting that you must weigh the advantages and consequences of each action. While it would be a good goal to elminate terrorism, remove a dictator, destroy weapons of mass destruction, and install democracy into a primarily dictator-controlled region, one needs to make sure you're paying a reasonable price to accomplish those things; there's perhaps a hundred nations that could use help from the U.S. military in building a stable democracy, and fighting terrorism. However, the US military, despite making up over 50% of the world's armed power, is still quite a limited resource for accomplishing those goals, so it would be best to choose the right countries to work in, where we would see the greatest, longest lasting result with the smallest cost.
It is on that utilitarian basis that I find the invasion of Iraq to be a gargantuan mistake. While it is obvious that everyone who likes democracy would be happy to see a dictator removed (any pro-Bush people who call people anti-democracy based upon their opinions against the invasion need to grow up, not just grow older), people who actually give issues some intelligent thought will not like paying a high price to accomplish such things. While it may have been good to remove Sadaam from power, he was perhaps among the least dangerous tyrants; the only nation he was really interestng in attacking was Israel, which is currently quite capable of defending itself against hte rest of the Middle East. Simply removing a dictator that has proven to be fairly docile for the past decade or so isn't a bargain when you have to sacrifice the lives of over 1,000 troops, thousands of civilians, the U.S.'s credibility across the world, as well as tying up the U.S. Army for the next decade or so, among other costs.
Currently, Osama Bin Laden remains quite free, and is suggesting that the U.S.A. is closer to another catastrophic terrorist attack than ever. Also, it seems that terrorist activity is almost (if not truly) at an all-time high, so the invasion of Iraq was innefective for combating terrorism (so much that I cannot count Iraq as part of the "War on Terrorism". AS for protecting any of the US interests, I don't think any of them are any safer; we've had plenty of reports of U.S. contract workers being murdered by guerillas. As for the Iraqi people, most are still without power (at least Sadaam Hussein had power back on for everyone in Baghdad within a week after Desert Storm), and the citizens of Iraq are still fearful of criminals running rampant, that were otherwise kept away by Sadaam's secret police forces. As for the WMDs, I don't think we've accomplished anything here; as the evidence shows so far, Sadaam truly did comply with the original UN resolutions of 1991, and removed all of them. Of course, every nation has the potential to develop chemical and biological weapons...
As a deal, I do think that the invasion of Iraq was a rip-off for Anerica. While a few of the goals were desireable, and accomplished to some degree, it was still too big of a sacrifice for such a small reward. The efforts should have been better spent on fighting enemies that actually did pose a real threat, such as Al-Qaeda.
Wake up, George Lucas... The Matrix has you...