Assuming that life is possible on other worlds, and that sentient life could evolve (2 rather large suppositions), what are the odds that the timing of that other world's evolution closely matches our own?
The first supposition is probably more likely than most people give credit for just because of the number of planets and stars in the Universe... I think probably a bigger problem is that aliens, if they are visiting us currently, would most likely have to have left their home planet long before we would have evolved or, alternatively, have appeared to evolved (the second assuming they had developed faster than light travel)...
And the "life on mars" stories refer to organic compounds, not sentient complex life. If you have other, more recent sources (from the mainstream media), please give links.
EDIT: @leavingwt Of course... especially depending on how you define primate. As far as alternative alien possibilities, I'm slightly attached to the intelligent amorphous blob, myself... Uses tools by extending itself around the item... How would we talk to it, though?