One thing I forgot to mention about the Smart Car - it runs on premium fuel only. That's crummy, as that puts it at almost the same cost per mile as the Toyota Yaris, which has four seats, (The Smart gets 36 combined mpg, whereas the Yaris gets 32 combined mpg - but runs on regular fuel. So when you compare the prices, they come out about equal. The Yaris wins, in my book.)
Just FYI, the similarly small Chevrolet Aveo gets a relatively bad 26 combined mpg. I have driven that pup, and it feels really cheap, as in cheaply-made.
Another downside is that there is a 6-12 month wait. You have to deposit $99 to put your name on a waiting list. I just can't figure out why the parking lot has 15 or 20 Smarts just sitting, waiting.