OK, nobody else is posting about the Smart ForTwo, so I'll be the first.
I have seen it up close, but not driven one and I have read a number of articles about it. Bottom line seems to be that it leaves a bit to be desired. Keep in mind that it only seats two, has rather limited storage, gets good but not great mileage (EPA rated 33city/41highway) and will set you back at least $12,000-14,000.
Interior is tall and feels roomy for two. Storage is limited but you could fit quite a few groceries in it if you went to the store alone and folded down the passenger seat. Because it is tall but short and narrow, drivers report that it feels a little "tippy", has a choppy ride, especially on pot-holed urban streets, and can be buffeted quite a bit by the air stream off of semi's on the highway.
The anemic 3-cylinder engine and slow-shifting, semi-automatic transmission force the driver to push the car to the edge of its performance envelope, especially on the highway, which can be exhilarating for some, scary for others. Its safety cell design performs surprisingly well in crash tests.
The Smart ForTwo gets lots of attention. A reporter for one of the car mags noted that crowds gathered everywhere he went. Interestingly, people over-estimated the mileage (some guessed as high as 80mpg) and under-estimated the price (some thought it should cost as little as $8,000).
For about the same price you could buy a Honda Fit or similar car that holds twice as many people, has at least twice as much storage space, gets similar gas mileage and is easier to drive. Its real strength is not fuel effficiency or price but its very compact footprint which helps overcome some of the challenges of owning a car in a dense urban environment. This raises a question, though: Do we solve some of these urban challenges by making cars smaller so we can cram in more of them or should we look for solutions which reduce the need for cars in such an environment?