Go one way. A "permanent" science station on Mars would do a world of good. Having people go there and come all the way back is ridiculous. Sure, they will never see a blue sky ever again, they can get used to pink. We can prefab inflatable buildings of very large size in which colonists could live.
People can be moved to the moon as well, to live out their lives in the service of science.

It's good to see a forum on this subject. Goodness knows it's all but been shut down by the government.
On a side note, it would be very interesting to see what the air density and composition is at the lowest point on mars.

@Pat:
Not much higher than at most other points on Mars.
@ Ross C.
I wouldn't do one way. It would be depressing seeing people landing on T.V. that will probably never return. I also don't like holding people hostage (even if the people are willing) to keep them alive on the surface. It could be disastrous for public support for further manned space exploration, as if we're going to stop at Mars.

Not sure anyone would be keen on a 'one-way' ticket ! However, one option would be a one-way ride on the outgoing craft, but ship a refuel and any other return journey necessities on another unmanned flight. In fact, several unmanned flights could go in advance to take supplies to enable a small base on Mars where astronauts could stay whilst preparing things for their return journey.
On a similar thought - would living in a pre-dug 'hole' be easier than taking up a building, as then you'd only need an airtight lining and a roof. Ship up some automated hole digging device than could prepare am accommodation 'hole' prior to the sapcemen landing and kitting out the accommodation within the hole.
And living below ground level will help balance the dramatic temperature variations on Mars - 110 degrees C variation in a single day. Also protects from dust devils and dust storms.

People who don't want to colonize Mars will never understand those that do. It should not be one way only but most the people who go won't want to come back.

I should have mentioned that I have a great-grandmother that to her dieing day refused to forgive he son in law for taking her daughter to the "Howling wilderness" of south-eastern Colorado. I am reliably told that the happy couple took a Model T Ford for the first trip and visited every few years. The old bat refused to come to Colorado by car, train, or jet airplane.

One way is the only way to go. But why drop again in a gravety well, why not stay "above"and go a little bit further to the astroids and start exploring en exploiting them. Find ice, make water and oxygen, find methane and make propellant, find rare earth metals and make a profit.

Power and lighting isn't an issue at all, nor is heating or cooling. A simple new design nuclear power plant would handle so many issues there. (unending power, a way to heat and cool, etc) I would also suggest in general updated gear...NASA and the shuttle program using tech that was build when I was a child should not be the norm. computers should be high end, light weight, and replaceable.I like the idea of the inflatable structure, more so because even if damaged, it is flexible and wont shatter if impacted which makes a larger problem. So many ideas....so little time.

i like the comment about using asteroids. however Mars has moons that could be used. the gravity well is smaller and could be used for refuel storage and potentially a fuel source if chemicals are found. it also has the potential for use as a base for solar system exploration. i do notlike the thought of a one way trip to mars when the fuel problem is solvable.

Where is the money? Maybe NASA can hire people to stand on every street corner with a sign which reads: Can you spare a dine for NASA?