It will really help lawyers and accountants who are going to be needed to interpret the laws. It is going to hurt small to midsized business owners, and it's REALLY going to hurt many of there employees, who will probably have hours cut so that the owners won't have to buy insurance for them. People who are healthy and take care of their body and are responsible for their health will also be hurt, as they will be needed to pay for the more sickly patients.
According to Obama, premiums will go down (I guess because of competition), but he will be tying the hands of insurance companies so that they put caps on out of pocket expenses. He is also making them insure people with pre existing condition (i.e. MUCH higher medical expenses). How this is supposed to work, I have no clue, but he also hopes that young people will sign up for Obamacare to help pay for the older/sick people. So it will also hurt young adults who may not want medical insurance. He never really explains HOW things are going to work when he talks, he just kind of assumes that it's "going to work". Sick people will also be hurt, as the focus on cutting costs is going to probably lead to longer wait times. Doctors will be hurt, as they will now have to fill out even more paperwork (although this is where lawyers will benefit).
Some people may benefit, but the VAST majority of people are going to be hurt by the law. I used to strongly support it until I actually took a closer look at some of the unintended consequences of it and noticed that with 20,0000 pages of legislation, most people don't know a whole lot about the law. Of course, the politicians don't care. Nancy Pelosi said "We need to pass this law so that we can find out what's inside."