Why would you want to send men? Why not a hundred more rovers.. They could do a LOT more and better explorations for a fraction of the cost. At this point in time sending men just does not make sense. Perhaps in the distant future, after we have completed exploration of the solar system there may be a reason but currently it is to early to send touristsLURCH, I've though the same. Sorry to say this but those lines are no hard evidence of water flowing on Mars. Of course the possibility increases with them, but we can't say for sure: There is liquid water on Mars.
As for colonisation: Why can't we use freezed water? (we know that there is such water on Mars, I think)
And finally, do you think we should send people on Mars to search for water?