To the extent that any war can be considered a success (which is very limited in my opinion), yes it was a success. Yes we went in under false pretences, but that doesn't necessarily mean it wasn't a success. While spending of any war can be considered wasteful, when you consider how small a portion of our yearly GDP was spent on this war, it was pretty cheap (using absolute numbers is a little disingenuous given that larger countries such as our own can spend more money without really noticing it). Also, while invasion may not have been the best method to achieve this, rather than a tyrannical, aggressive, and all around jack ass dictator controlling a country with the largest military in the already unstable and oil rich Middle East, we have a relatively stable (stable enough that no insurgency is going to overthrow it in the foreseeable future...the lack of a North Vietnam equivalent is where comparisons to Vietnam fall flat with this war) regime that is basically democratic (more so than the Karzai regime in Afghanistan), non-aggressive, and proving at least somewhat capable of crossing the Sunni-Shia gap. Also, Iraq is beginning to recover economically after a decade of embargo and three major wars in the past 20 years (their economy is grew at a brisk 4.5% in 2009 and grew at a solid 7.8% in 2008). It has lots of problems but with the insurgency dying down (the 2006 civil war was decisively won by the Shia, and they have no interest in overthrowing the current regime), Iraq lots set to rejoin the international community.
Iraqi Freedom was messy, filled with blunders, and probably not the best way to get the end result we have, but I don't think the Middle East or Iraq would be better off with Sadaam still around.