I really don’t want to defend McCain/attack Obama, but I’ll bite. The difference is that Obama is close to becoming the messiah to his supporters.
[Also, for the record, a B-movie actor isn’t really a celebrity.]
I’m not much interesting in politics either, reasons similar to Ms Contrarian’s oversimplified one. However, I think this election has a chance to be different. If Obama becomes president, he will have a heavily Democratic Congress and an adoring press fully behind him. It’s not much of an exaggeration to say that his supporters think he is god-like. This combination does not bode well for Libertarians. Perhaps it is generally ok to ignore politics to avoid having to decide between the loss of our social or economic freedoms, but this may be a case in which the winner will have tremendous ability to take those freedoms away very quickly.
(Or it may not be. Obama seems relatively pragmatic, so far. I’m just saying that he will be very well positioned to do bad things, if he wants to do so).