Concrete is WAY too energy intensive of a product for most applications. However, there are too many fallacies in this comment to ignore.
1. needlessly complicated structures exist in steel and wood form, too
2. point is unclear, but again, how is this specific to concrete?
3. same comments as 2.
4. concrete does hold together. It functions much better as a compressive material, though, which is why when there are tensile (or high shear) stresses, steel is added. There are a lot of unreinforced concrete structures. I've heard comments from a concrete guru that reinforcing any slab on grade is ludicrous.
5. concrete doesn't have to break before it works. Not sure where you're interpretation comes from, but it's off base. Reinforced concrete structures are designed for ductile failure as a safety precaution for users. This means that the concrete is expected to crack at points of high tensile stress. Engaging the steel will result in obvious indicators should the structure begin to fail. Without this, the structure would fail in a brittle fashion, which means that once the breaking point was reached, the whole thing would come crashing down on anybody who happened to be under it.
6. all structural materials in their virgin state will decompose when subjected to the elements. And it's salt transported by water that rusts the steel, not the water itself. This is one of the reasons that structures have building envelopes; to protect the materials holding up the building.
7. Uhh huh, and...
8. .. this is why concrete is mostly appropriate for large loads and long spans. Try building a multi-story building out of rammed earth.
9. wait, what?

10. Okay, woah, this has to do with building design and is again entirely independent of the structural material.
11. concrete a conductor? listen, one of the advantages of concrete is that it absorbs heat during the day and relases it slowly during the night. same as adobe.
12. agreed, unless, hold on, wait for it, you wear gloves and a mask. -gasp-! oh the horrors!! Forget abhu graib, let's go after concrete construction sites!!! Seriously, don't trivialize the word torture.
13. Call the selkirk hospital, one got loose
14. agreed
15. not even close, brother. Take a look at http://www.canadianarchitect.com/issues/ISarticle.asp?id=143336&story_id...
or do a search for fabric formed concrete.

Let's not forget that concrete has made it possible for dense urban life. Without concrete and modern steel, we'd still be limited to buildings of a handful of stories in height.

Concrete has been used for a very long time, and when properly designed, lasts many centuries. The Pantheon is an example. The most commonly used type is Portland cement, invented in 1829. Some of the first PC structures are still in use. Many alternatives have been tried before and since. Some are better, but require more skill, quality control, and energy to make. And to borrow Matt Simmons' line, it costs 8 cents per pound. What else can you buy for that?

For a few thousand years, mankind built mostly with stone and earth, and lyme and wood. Then, with the beginning of the fossil fuel age, some smart guy figured that if he crushed the stone, burned it in an oil or coal oven with a few more components, and packed it, he could sell it for a much higher price as a sort of "fast stone", once mixed with sand and water. Not just a binder like lyme mortar, but something that could be shaped and stand for itself. And marvel people at it's tensile strenght, once reinforced with steel. Never mind that stone itself would last and be useful for thousands of years, and "fast stone" only for around fifty.
Cheap fuels, both for fabrication and transport, enabled the thing to spread and indeed form the basic material of the infrastructure of industrial society, in a widespread manner since WWII. Every wonder of the modern(ist) world, from high rises to suburbia, autobahns to war bunkers, Corbusier to Zaha Hadid, would not exhist without concrete. It is present in a most obvious form in Brutalist architecture, but without it as foundations even steel and glass high rises or humble mac mansions would not exhist as they do. Concrete can even claim direct responsability in hundred's of thousands of deaths in earthquakes around the world in recent decades, as you could verify recently in China. People were crushed under piles of concrete plaques from buildings past their (short lived) safety age, or built without any respect for the laws of tectonics and safety, something that concrete enables like no other building technique.
Both materially and symbolically, concrete embodies the futility and aimlessness of industrial civilization. Short lived but lucrative for industry, archtecturally amorphous but able to be shaped to the whims of one high priest of modernism after another, concrete stands as a more visible proof of the futility of the oil, or fossil fuel, age, than extensive motoring or aviation, and yet it has been "taken for granted and natural", as Snomm remarks in his excellent post above. As it's dawn aproaches, together with Peak Oil and the Age of Incredibly Stupid Use of Resources, we will be left with a mass of decaying structures around the planet, uninhabitable by societies that can no longer occupy the land like they did in the times of oil utopia.