McCain winning would be funny. In four years we'd be reading about how the war in Iran was a great idea, no troops out of Iraq and who the heck knows where the economy will be. McCain will be a million years old and Obama will still be black so people will have to come up with some new reasons why the change was a bad idea.
There will also be serious campaign finance reform if McCain manages to win. There's no way Palin could beat that money raising machine without the laws being changed.
One upside is that McCain should, in theory, get to appoint at least one justice. That should shut the right wingers up and make the next election less "life and death" for them.
Security for Obama would be too expensive for taxpayers and he may have to keep a very low profile in the senate.