I hope you guys realize that the gravity on mars would cause great harm to your body over time.
Since artificial gravity doesn't exist, I can only imagine what kind of health problems would arise from being off the earth for that long.
Terraforming mars is a hopeless task. Without a sufficient magnetic field, the atmosphere will continue to be lost to solar winds etc over time.
Don't get me wrong, the idea of being on another planet is certainly very exciting, but realistically we need to accept the fact that saving the earth is our primary short term and medium term goal.