People will go to Mars for the same reason they sailed into uncharted oceans, hiked to the south pole, and my cousin bungee-jumped from a hot air balloon. They will go there for no other reason than that they can. It's just a matter of time. Any argument over whether or not they should seems pointless to me, if only because we all know that sooner or later they will.

I don't think it is a grand idea to try doing so now, or anytime soon, for reasons already stated. But I have no problem with the idea of starting to climb the ladder to mars now, learning to do the things we need to do (and in some cases have already done & forgotten) to get there.

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The point of philosophy is to start with something so simple as not to seem worth stating, and to end with something so paradoxical that no one will believe it. -- Bertrand Russell