To a European, your representation of Obama as an extreme socialist/borderline Marxist actually seems like a joke. Don't take that the wrong way, it's just that we have actual socialists here and Obama's politics really don't fit the bill. Over here he would be regarded as somewhere in the centre.
I know I'm not qualified to say, not being an American and all; but I think you're "Neither, really" just about sums it up. Which is a real shame.
Compared to what the American system has been, Europe (and Canada) itself is more socialist. What Obama wants, the appeal he made in Berlin really, is for America to become more "world citizen" along the European line of fraternity. He wants more government money being spent on semi-socialized health care, more money going to a government approved education, and along with the Democrats like Pelosi, he would be more amendable to more government regulations on free speech. Namely they would want right wing talk radio shut down in the name of 'fairness'.
this is something that Europe already has. Europeans and Canadians too are more used to having more goverment in our lives. This is the change that the democrats are looking for.
There is no crisp, clear lines of demarcation between America and Europe of course, but Obama and the Democrats are much more interested in equality of results where the rich are taxed down closer to the level of the poor, and disparity is thereby reduced. They want a strong central government capable of controlling all aspects of society, not so much against the capitalists, but in cooperation with the big business and big labor. This is not to say that they are against the capitalists of course and that they want the state to run the economy like in capitalism. Rather there are more into a cooperative venture with the capitalists, like Warren Buffet, for example, who fully supports Obama, as do many other capitalists.
Contrary to popular opinion, the typical Republican voter is not a sleek Wall Street banker, but as often as not he is rural working poor who is just not interested in what big government has to offer.
This is not to say that Republicans are not in the back pocket of capitalists either, btw. What is more true to say though, is that there is still a strong wing of the Republican base, energized by Palin, who have a strong distrust of government and who want government power limited. This Republican base is almost wholly missing in Canada and Europe too I think, but it is still very much alive in America.
In terms of Catholic doctrine, as laid out by Leo XIII and the doctrine of subsidiarity that arose from his teachings, people should be enabled to control their lives as much as possible. More than either Obama or McCain, or Biden too, Palin's approach to government in my mind captures the essence of this doctrine.
It is her that has captivated the Republican base for the Republicans and not McCain.