If you don't have time read more than one of the hundreds of Bush legacy pieces appearing all over the blogsphere and print media, then read this one. It really tries to be fair--pointing out that some of the things that happened during this miserable administration can be seen positively--and as a historian, schooled to carefully weigh all sides of the argument or issue, this appeals.
On the other hand, if you have time to read more than one assessment of the Bush years, then I suggest you can start with this one or this one, only 157 words, to get the story from people who are also fair in the sense of calling something by its right name, no euphemisms. But my favorite is this one, a withering blast at a nincompoop who was at least two or three levels above his overall level of competence. The Peter Principle in overdrive. It's entitled "The Greatest Greatness of George W. Bush," and it ends with the stirring send off: "May you live forever, you son of a bitch." I loved it.
Fact is, if you take "objective" to mean "truthful," it's impossible to lie about this guy. He has run the country straight into the toilet in just about every single area--other than the area of earning the contempt of the world. How can you be even-handed about that? Why would you want to?