It makes as much sense for you to call Obama a Marxist as it does to call Rush Limbaugh a Hindu.
Obama isn't even a communist, even if he's forged alliances with communists in the past for political gain.
Karl Marx was a philosopher and economist of the 19th century who would be a footnote in the history of economic thought had his ideas not inadvertently influenced half the population of the globe, and served as a philosophical basis for the Soviet Union, Communist China, Cuba, North Korea, Vietnam, etc.
Why do I say inadvertent? Because Marx wasn't a malicious totalitarian (misunderstandings of the term "dictatorship of the proletariat" notwithstanding), he did not advocate, and even implicitly or explicitly opposed many of the tactics later put into practice by communist countries--tactics and policies which were purely hypothetical in Marx's time but which were nonetheless considered by communists at that time as possible courses of action.
Marx's own opinions were all wrong (anything he said that happened to be true was existing economic theory that he had studied), but he was also taken out of context, distorted, and misrepresented by people claiming to be his followers. And that just in his lifetime, he himself said "I am not a Marxist."
Whatever you can say about Marx, he never planned for a brutal police state (indeed his views on fighting crime centered around changing the social environment, not on more policing), brainwashing propaganda, education being controlled by the state for its own ends, a body of central planners deciding everything in the economy. Quite the contrary. In fact, the alleviation of poverty via was not his aim, it was rather incidental, a side effect, a natural outcome, to his true aim: to free mankind of all restrictions and allow him to reach his full potential. That's how he saw it anyway.
Now, I happen to think that a free country with a free market and a system of law and order allows that to happen far better than a communist country, and I sincerely believe, based on my understanding of Marx the man, that if he were alive today he'd recant his belief in socialism and become a libertarian free marketeer. After all, he valued empirical fact and logical reasoning, and now that socialism has been discredited in the eyes of all serious, non-political economists, he'd have to admit that the free market works far better than he originally thought it did. Economic theory has come a long way since the 1800s and the economies themselves have developed.
As the world economies modernized and became less and less dependent on simple manual labor, standards of living soared, productivity soared, mankind's potential to fulfill his own destiny has soared, and people have more freedom and options and luxuries than ever before.
Never forget that Marx believed that the free market was not something to squash, but a necessary step in mankind's evolution, as were the hunter-gatherer stages, the tribal stages, the feudal stages, the mercantilist stages, etc. Given how far economic theory (and economies themselves) have advanced since then, he'd have no choice but to admit he was wrong about the free market. And he certainly would weep with shame at his name and his face being attached to the horrors of real-world communism.
Back to Obama...
In no way, under no definition of the word, can Obama be called a Marxist. He is not a follower of the historical Marx, nor is he one of the vulgar Marxists who never gave a fig about economics or what Marx really said. Obama has borrowed a lot of communistic rhetoric and approaches, and he's appointed communists or far-left nutbars to meaningless, just-for-show cabinet posts (really, a "green jobs" csar? nothing more than a PR stunt), but where the rubber meets the road, where the real economic policy of the administration is devised, he has hired mainstream market economists. Christina Romer, Larry Summers, Austan Goolsbee, etc. These are devotees of the so-called neoclassical synthesis, a take on Keynesianism that incorporates classical micro and macroeconomic thought and has become even more grounded in free market economics after the influence of the Chicago School and Austrian School. He reappointed Ben Bernanke as "head" of the Federal Reserve Board, another mainstream economist (who fully recognizes that the Great Depression was caused by the Fed in the first place).
This shows that Obama has no intentions of communizing America--this isn't the crowd he'd hire if he were. Heck, he could have surrounded himself with even more far to the left (but still mainstream) economists such as Krugman, Stiglitz, Blinder, Tyson, etc. (and indeed many of these characters have worked as informal advisors at one point or another), but for his core economic team he chose mainstream market economists. He could have gone whole-hog heterodox and hired nothing but Galbraitheans and socialists and communists to devise his economic policy. But he hasn't. So stop saying he's a Marxist or a communist, it just makes you look foolish and extreme.
Now I'm not naive, clearly Obama sees a larger role for the government in peoples' lives, he clearly wants to shape society according to his own vision rather than letting the dictates of the market (i.e. the demands of the people themselves) shape society. But he's not so stupid to think that he doesn't need economic growth to fund his projects and that requires a market economy. It needs businesses turning a profit and hiring people, it needs people getting rich, making millions, people spending their money on stuff. He's under the delusion that the government can stimulate growth, but he's not so delusional that he thinks the government alone can make the economy "run."
So what role does Obama see for the government? Clearly he sees a larger welfare state. Indeed, making people dependent on the government for something as basic as their health care guarantees that the welfare state will become a way of life for the whole population. It puts a floor on whatever government-shrinking measures reformers will try in the future. Nothing short of a world-war level catastrophe or depression-level recession can create enough turmoil to force a government to drop socialized medicine, once enacted. Or a very severe debt crisis.....
He sees greater government involvement in education, in using education to foster collectivism and "volunteering" as an end to itself. I don't think Obama has any grand end in mind other than being able to shape society according to his vision, or the vision of "people like him," i.e. elitist leftists who never produce anything of value yet are wealthy anyway.