Personally, I think all of the issues are important...and there are issues of importance that are not listed...
In order of importance I would have to say:



1) Economy ....because without a robust economy, people cannot have access to any kind of quality of life, and social constructs begin to break down

2) War In Iraq ....until we get out of Iraq, and free from the quagmire of lost lives and the financial drain it imposes on the American people, our economy and our morale will continue to suffer

3) Terrorism ....until we address our open, porous borders, and we target, specifically Al-Qaeda, in Pakistan and Afghanistan, and acknowledge the complicity of Saudi Arabia, Syria, Iran, then we are fooling ourselves, and had better brace for the next 9/11 type attack.

4) Climate Change ....are you kidding? If the polar ice caps melt (as they are doing), and coastal regions flood, and strain economy (and tourism), and population overcrowding are the results....things are going to go from bad to worse, and make Katrina and the midWest floods seem like a day's outing.

5) Health Care ...if we don't have universal healthcare for everyone...then you might as well tell large segments of the population to just "suffer and die". For some, that is no big deal...but for folks with loved ones, and family affected, it is a very big deal. Not saying that preventative medicine is not a component, and that people have to be sensible and pro-active in their own lives.
6 & 7) Immigration & Globalization are linked, inextricably...the problem of what to do about the illegals who are here, is problematic....some are assets, some are drains....some are criminal, more are law-abiding...globalization is about keeping competitive with jobs, education, and productivity. Duh!
8) and lastly, Social Issues (Abortion, Gay Marriage, etc.)
sadly, the last things to be considered, but critically important to many....goes along with the belief that everyone, meaning "everyone" is entitled to the American Dream, by being an American...you either embrace that belief, or you're something of a hypocrite.