He was governor of a state. A VERY similar (albeit smaller scale) job to being President. States have Judicial, Legislative & Executive branches, constitutions to follow and individual counties to oversee, just like states.
Obama, by contrast, has actually logged less than 365 days as a Senator; the only political position he's ever held.
I agree neither is a perfect choice, but McCain is genuine, has genuine political & military experience and at heart is a centrist (like Bill Clinton): too left for the far right and too right for the far left. What's left, however, is most of us.
Obama is a far left, Socialist, racist with very questionable proposals, statements & associations under his belt. All he really has going for him is his charisma and the fact that he isn't from George Bush's party, which is the major thing hampering McCain. Only a fool judges people mainly by party affiliation though. I don't judge all Dems as Jimmy Carter, so don't judge McCain by Bush.