I'd say the Fiat 500, definitely. It's not quite as small, but we got one several weeks ago - a Sport, manual - and so far we think the Fiat is an awesome car. 33-34 MPG for our typical driving style, which probably trends more to city than highway. My wife just took a 260-mile trip, largely on lightly-traveled state routes, and hit 43-44MPG. The Fiat handles well and is comfortable and looks decent inside and, of course, is available with a manual transmission and a stability-control-off switch (though the latter we think just raises the limits, sadly).
The 500 replaced our smart car, which was actually OK but which desperately needed smarter transmission software to help it figure out that a small lift off the throttle did not always mean "upshift now!", sometimes it meant "I need to scrub a little speed so I can see if I need to commit." The delay in waiting for the upshift to complete, then waiting for the next downshift, then waiting for another downshift, could get pretty frustrating. On the flip side, exploring the smart's handling limits could be entertaining (seriously) and the fact that it's rear-wheel drive is great.
I like car magazine's capsule summary of the smart: 10 years ahead of its time... 10 years ago. You always got the impression that it should somehow be a bit better than it was.
We'd also been holding out for the iQ, and we might have toughed the delay out, but the news that it'd only come to the US as a CVT was a deal-killer for us. Why replace a car whose automatic transmission we dislike with another car whose automatic transmission has not been well reviewed? Especially since we prefer manuals anyway...