While I agree that commercial space outfits need people, I disagree with your absolutely stated position that humans are not needed in scientific exploration of space. Let's take a look at the Mars Rovers for a great example:
In all their technical ecstasy, they are slow -- they take forever to do any task, whether its to drill an amazing "life finding" 2cm into a rock, or move across the landscape. A simple rock throws them off course and gets them stuck for days while people back on earth, through video cameras, spend weeks trying to get the wheel unstuck in a delayed communications nightmare. Dust storms can completely kill their ability to power themselves, and built up dust diminish the power they can draw from the sun. Advances in AI have been crap in comparison with the other developments in technology. Their "brains" are spread between Mars and Earth and a brain that can think at the speed of light is what we need here...
First off, NASA's two Martian orbiters, through which information is relayed to Earth, can only transfer a single megabit of data per second. Worse still, these orbiters only work in 15 minute increments before they must be repositioned -- a process that takes hours. Furthermore, bandwidth is unsurprisingly limited on the Red Planet -- messages between Earth and Mars usually suffer 4 - 20 minutes of lag, depending on the positions of the conversing planets.
People, on the other hand can diagnose and repair computer and equipment problems themselves. They have use of their senses and high developed brains to identify and troubleshoot issues. They have the ability to do "boatloads" more science, like pick up a damned shovel and start digging a 6 foot hole to find fossils... Or simply the ability to pick up a rock with their fingers and look at, or smash it open with a hammer.
Additionally, humans can take samples on Mars back to labs on Mars (which is what the whole Mars/Ares mission will have, as labs and habitable quarters will arrive separately and will be awaiting the astronauts) and analyze things there, with educated humans, instead of using crude tools on robots to analyze some of the most important scientific data to mankind.
I know its more dangerous and sometimes robotic probes and rovers make more sense, but it is just the opposite sometimes... it makes more sense to send a human to do a human's job. On top of that, human's need a challenge to keep us focused and growing in a positive direction, and conquering space with manned ships is a great approach to what we need to do. Giant interplanetary (and eventually intersolor) starships with the ability to house groups of experts to study the science of our planets, the stars, and everything else will do more than any group of robots ever could!