Well now. I cant believe I am writing this on a forum which ostensibly deals with video games but here goes.
To begin with, lets begin with the man himself, Karl Marx. Its important to keep a few things in mind, firstly Marx never said that Capitalism was inherently evil, just that it was a necessary economic development, a major step forward from the previous socio-economic system which is Feudalism, but in which due course must make way for an ever more progressive system. The choice between living in a Feudal society on one hand and a Capitalist system on the other is I think quite obvious.
Secondly, Marx critiques the Capitalist system, and explicitly maintains that at the end of the day the only way to change matters is by people, aware of their social conditions, decide to act in a concerted effort to change the system to a better one..i.e Socialism and then Communism. In this he saw the Proletarian (Working) classes as the only group that was best able and determined to change it. For him the final analysis is economic, but one that is ultimately dependent on Human Volition.
Thirdly, Human progress for mark is an iterative process. ALL steps must be taken. One cannot take a feudal society and convert it into a Communist society simply because for Communism to exist a FULLY developed Capitalist society must first come into being. You cannot have one without the other. This unfortunately is the case in almost every ostensibly "communist" country.
The Soviet Union was built on feudalism not Capitalism. It was a primarily peasant society which effectively practiced serfdom. This is not fertile ground for Communism, for a multitude of reasons which would take too long to explain here, see above. Lenin actually was struggling to bring a proletarian class into being by trying to create a hybrid CAPITALIST / Socialist economy. He even admitted later that this was not what he wanted.
Apart from the Soviet Union, almost every non-European country which is considered communist is either colonial, feudal or malformed in its institutions at the time of its revolution. For Communism to come into existence, it would need a highly industrialized and stratified society for revolution to take place. Mainland Europe managed to offset the tendency by the Welfare state, combined with massive infrastructure and public works projects that allowing it to become far more egalitarian than the US. The UK followed this model to a degree, but like the US began dismantling its welfare state with the Thatcher / Reagan years.
In the US the combination of Keynesian policies by FDR, the post-war boom and a concerted effort by the government to root out Communist cells through a combination of sophisticated propaganda, surveillance and persecution ensured that any form of socialism was cut out at its root. Once the Soviet Union began its inevitable decline, the US then began to substantially cut back on its welfare policies, culminating in the Chicago school of economics and Milton Friedman. Which incidentally has sparked the greatest economic crisis since the Great Depression, and turning the US into the largest Debtor on the planet.
To summarize: Communism cannot exist without a Capitalist system to come into being, it cannot come into exist without a concerted effort by the multitude.
Communism is aimed at the development of the Universal Human. A being who is poet, artist, philosopher, scientist, statesman, and worker; to the extent of his innate abilities and inclinations. IT IS NOT THE SOCIETY OF EQUALS. Atleast not in the sense that all people are equally gifted or equally inclined to cultivate their latent talents. Communism is a society where no sphere of human endeavor is denied to an individual for him or her to cultivate to the best of his or her abilities. It is a society where every opportunity to cultivate ones abilities are provided, without hindrance from social or economic difficulties.
To put it crudely; Communism doesn't care without you say an object belongs to you, just that the means on that object's production is collectively owned by all, with everyone having access to it. The concept of "ownership" would become meaningless, for while I may lay claim to an artifact solely for sentimental reasons, I wouldn't claim that I in a legal sense own that object, nor would anyone ELSE try and take the object from me. Why would they? Since they have the same level of access to productive forces as I do, they can say, just as well make one of their own. Theft can only exist in a society where the access to the means of production and the associated resources is uneven. The only other possible reason would be clinical insanity.
Finally COMMUNISM IS NOT THE SOCIETY OF JOY. Communism doesn't say everyone has an god given right to happiness, merely its unhindered pursuit. The perils of the Human Condition from sadness, to shame would still be with us. What would perhaps not be there is *shrug* fear I guess. Fear of lacking the basic necessities, fear of one's fellow human beings, fear of being thwarted in ones pursuits. Communism is not concerned with joy, its concerned with Justice.
As for Capitalism. Well to put it simply: It doesn't exist. There is no such thing. What people call Capitalism today is as far removed from the vision of Adam Smith as Communism is removed from Karl Marx. For Capitalism to exist, one of the key tenants is COMPLETELY free movement of Capital and Labour with absolutely NO INTERVENTION by Governments acting DOMESTICALLY OR INTERNATIONALLY. Closed Borders, Tariffs, Cartels, Trade Barriers, Economic Nationalism, Military actions against other actors to control resources - all of which has ALWAYS been practiced by the Standard bearer of Free trade - the USA.
The current recession (depression?) is a case in point. The Government had to bail out the banks by tax payer money and initiated a war against another nation for the de facto strategic control of its oil and location. The coming Bailouts for the car makers coupled with what will most certainly be cuts in public works is about Capitalist as the Soviet Union or China is Communist.
I am to get into a shouting match about where the USA is heading, I prefer not to speculate. All I can say is that the track record of De jour Capitalism as it is known is no better than de jour Communism.
The ideology you choose to support then comes down to a simple philosophical and ethical question: Is man noble?