There's an article in Salon by Mike Madden called, "Obama Wants to Kill Your Grandma: Five right-wing myths about healthcare reform, and the facts." If you look at each supposed myth, what you find is that most are actually based on reasonable concerns. I don't think that's what Madden intended when he wrote the article.
Myth 1 is found in the title, Democrats want to kill your grandmother. Obviously if you put it like that, the idea is completely ridiculous. And of the five supposed myths that Madden attacks, this one is his best argument. Fears about government-sponsored euthanasia are based primarily on paranoia. But there is legitimate concern that health-care rationing will deny life-extending care to the elderly, because it isn't considered cost-effective. Madden ignores that argument, which is more prominent than conspiracy-theory thinking about government euthanasia plans.
Myth 2 isn't a myth at all -- the question of tax-payer funded abortions. The only reason publicly-funded abortions are not part of the current health reform bill is because of major opposition. Such funding would certainly be in there if proponents though they could pass it. Madden's attack on this as a myth is pretty disingenous.
Myth 3 is Obama will ban all private health insurance. Again, Madden is relying on technical details of the current proposal, whereas opponents are looking at the implications, both long and short-term. Even Madden admits that the current bill will restrict how private plans can operate and be purchased. He ignores the actual arguments and concentrates on the semantics in order to declare a "myth."
Myth 4 is the government can't possibly run a healthcare program. This one is just a blatant mischaracterization of the main opposition argument. Most don't claim that the government can't run healthcare, they argue that it will do a terrible job. Obviously that claim is debatable, but there is nothing in it that qualifies as "myth."
Myth 5 is another non-myth, but rather a fact: unlike private insurance, government bureaucrats will ration care. Madden pretends that because private insurance also has bureaucrats who make healthcare decisions, somehow this argument is a myth. Apparently Madden doesn't understand the difference between dealing with a private corporation and the government, as well as the difference between a fact and a myth.
Overall Madden's arguments are pretty weak. He has to rely on specific semantic wordings of opposition positions in order to characterize them as myths, and even then, most of his attacks are unconvincing. He really only identifies one actual myth.