As someone mentioned earlier in this thread, the electoral college helps make flyover states relevant. Do you think anyone would bother to campaign in the Dakotas if there wasn't the EC? All the campaigning would be done in CA, TX, NY, FL, PA, IL, OH, GA, NC and MI.
Also, if the presidency was decided with a straight up direct vote, then the Dems would have won the last 8 elections (if I'm remembering correctly). The last GOP president to win the popular vote with Bush Sr.. I'm not including Bush Jr. second term because it was still so close to 9/11 and the country was in the midst of two wars. That might be unfair, but I remember how he was going before the attack. It would have been hard for him to rebound and get re-elected without the attack and following wars.