Communism/Socialism are good ideas on paper, but the trouble is that these systems apparently don't have much in the way to stem corruption. I say this because you can look at a country like China, where bribes make the world go 'round, or Communist USSR, where Stalin tended to have you killed at the drop of a hat (the fellow did more ethnic cleansing than Hitler) and it's pretty clear what happened is that the people in charge allowed the power to corrupt them.
These systems could work if the government was run by angelic, uncorruptable individuals whose ability to rule was tempered by godlike intelligence and forbearance... but good luck having such an individual climb to the pile of popularity and stave off natural monkey-mind tendencies towards corruption.
That said, Democracy hasn't exactly removed corruption, so much as has limited and redirected the infection a bit. As the Neocons have been demonstrating fairly compellingly, we've got corrupt senators very much on-the-take from lobbyists representing fat cat businesses who are every bit as willing to profit off of human pain and suffering as anyone else in human history. Power still corrupts, it just moved on to corrupt certain individuals who have amassed it (lots of personal wealth).
Ideally, the population is supposed to be intelligent enough to recognize corruption when they see it and snuff it out by not voting for those candidates. What actually happens is we're all so completely snowballed by our candidates slick campaigns to the point where it takes formidable critical thinking to have any chance to penetrate the smoke screen. Because so few of us have that kind of time or energy, Democracy emerges, as our founding fathers have feared, as a baseless popularity contest.
In the end, politics has always been about herding cats, both at the bottom and at the top. Piss off enough cats among the bottom, and you get overthrown. Vote a cat to the top, and they're tempted to try their feline wiles at skimming the cream off society and getting away with it. Any political system is only as good as the intelligence of the people who make up the society. Anarchy is not the answer either, as it simply creates a power vacuum for us to be gobbled up by societies which cooperate on a larger scale.