1) Began the neccessary wars to destroy terrorist organisations in the Middle East which threatened the USA and it's Western allies safety and democracy.
2) Liberated the combined countries of Iraq and Afghanistan and undoubtedly added fuel to the fire of democracy movements globally. That is, at current population, 68 million more people living under far fairer and democratic modes of government then previous.
3) Prevented further domestic attacks on US soil after 9/11. Restored faith in American instituitions like the military and intellegence communities.
4) Renewed solidarity with Israel but also offered out an olive branch to the Palestinians by referring to a future "two state solution". No other President has uttered those words.
5) Funded mass Anti-AIDS/HIV drives in the most deprieved regions of Africa. Saving millions of lives and prolonging others. He has prevented untold agony and misery.
6) Removed one of the most evil despots of the past 5 decades in Saddam Hussein and destroyed the Taliban which wrecked Afghanistan's cultural history (massive buddhas

) and forced it's population to live under a hellish Islamic fundamentalist therocracy.
Probably loads of others too. GWB will get plenty of praise in the future by historians. It will take a few decades mind.