Most Americans will be affected by the overhaul of the nation's health insurance - some more directly than others.

Here is a look at four people - an uninsured woman with a pre-existing condition, a man happy with his current insurance plan, a college student and a self-employed professional - and how the new healthcare legislation will likely affect each of them in both the short and long term.

Individual experiences will vary, but some glimpses of the future can be seen already.

Laura Carpenter, 56, uninsured, Tuolumne, Calif.

At the same time she battled non- Hodgkin's lymphoma, Carpenter fought with Aetna U.S. Healthcare about its repeated attempts to cancel her insurance policy.

She was cut off for the final time - in September 2004 - because of what she describes as a simple postal error. At that point, Carpenter, a former marketing manager, was left without the coverage that paid for most of her treatments -- treatments that she believes ultimately helped her beat cancer.

Unable to find another plan she could afford, she's now been without insurance for more than five years. It's been that long too since she's seen a doctor for follow-up tests related to her diagnosis. For Carpenter, health reform is a very welcome turn of events

"When I heard it was going to pass, I was kind of blown away it actually happened," she says. "I'm feeling cautiously optimistic. At this point, it would seem almost too good to be true to have coverage again."

People with pre-existing health conditions, such as Carpenter, are among those with the most to gain from the impending changes to the health insurance system.

Within 90 days of the bill becoming law - around mid-June - a new, but temporary, national high-risk pool for people with pre-existing health conditions will be established, extending the option to buy coverage to those who have gone without insurance for six months or longer.

Starting in 2014, the high-risk pool will be eliminated as people gain access to insurance through a national exchange, says Anthony Wright, executive director of Health Access California, a statewide advocacy group. Carpenter will then be eligible to buy a policy through the exchange, with the guarantee that her coverage can never again be pulled away.

Carpenter has gone for years without recommended post-cancer treatment checkups. She looks forward to going for doctor visits she's long been unable to afford, and to putting her mind at ease.

"In the back of my mind, I keep thinking it will be worse down the road because I didn't take care of some things," she says. "I have a list as long as your arm of illnesses I've had related" to non-Hodgkin's lymphoma.

Upon becoming eligible for health insurance once again, she says, "I'll probably get the tests done right away that I should have had before."

-Lisa Zamosky

Laurence Rudolph, 62, Herndon, Va.

Rudolph, an independent contractor, is happy with his health insurance as is. The Blue Cross Blue Shield plan pays for preventive care and diagnostic tests and is accepted by the primary care physician who has a long history with his family.

"My wife's plan is not cheap … but it is a good plan and well worth it," he said. "Peace of mind is worth a lot."

And nothing in this law will require him to change his current insurance, said Anthony Wright, executive director of Health Access California. Not only will he get to keep the coverage, which he has through his wife's job with Fairfax County Public Schools, but the family policy also costs less than $27,500 annually, the threshold for being taxed as a so-called Cadillac plan.