Regulated Capitalism, is the reasonable middle ground.
Socialism as a definition, must inhibit individual enterprise (and thus our personal dreams and ambitions ) so as to control wealth distribution.
Free-for-all Capitalism with no social safety nets or taxation, equates to suffering for many in society that often need help.

The Western world in most cases finds a good balance between the two. Capitalism as a base mechanic, allowing for individuals to build wealth and prosperity for themselves and others, with safety nets to help the unfortunate.

I think that socialism and representative democracy is apples and oranges; unless I'm misinterpreting your question. I believe that you are asking to compare socialism to capitalism. In theory, with a representative democracy, you could still have socialism in place.

To actually answer your question: I think that socialism and capitalism are each flawed in one fundamental way. In capitalism, like in a game of Monopoly, one person will end with all the money. If one person has all the money, what's the use?

The flaw with socialism, however, is Human nature. In order to make sure that each person has an equal share of the money (and/or product,) it must all be pooled together and then redistributed. Someone will have to be in charge of the pool. nothing in particular stops that person from taking whatever they like out, or from not distributing the product evenly.

I do think that eventually socialism will have to be implemented across most of the world, due to capitalism's potential for all the money to end up in one hand. Unfortunately, until we find a way to have an unbiassed party mediating the communal chest, socialism will be unable to work.

The second part of your question, whether we already have a socialist system, is quite debatable. What is known as progressive taxation does at least shorten the gap between people of different wealth brackets, but someone who is taxed on 50% of their $10,000,000 income will still make a significant quantity more then someone who is not taxed at all on $100,000.

Progressive taxation is not in place by any significant quantity in the United States, but I can't speak for the rest of the world. President obama has expressed interest in implementing such a plan though.

To answer the question as directly as I possibly can: Yessish.

Practically every government on the face of this earth uses a combination of socialism and capitalism in it's economy, as has practically every government ever created. Socialism and capitalism are symbiotic parts of the human economic condition. Capitalism is most often found at the lowest end of the economic scale. Socialism is most often found at the highest end of the economic scale. The times when capitalism is most prevalent is during the expansion of one culture into an area at the expense of another culture so that the culture expanding does not pay for the resources it is acquiring, for example the expansion of the Europeans into the Americas.
The time when socialism is most prevalent is during times of upheaval and during times of war. So socialism was very prominent in Europe during the transformation of Europe from monarchical systems to republican systems, and during the period in the United States from 1940 to 1945 when almost all of the economy was regulated. The most peaceful the time, the more likely that capitalism will flourish. At this moment in our history, we are in economic difficulty and at war so a drift toward socialism is on the rise.

Go to Canada if you want a socialism state. You will love that place and you will hate what you took for granted in the USA.