You should state your requirements clearly, if you need the space, settling for a hatchback will frustrate you despite good fuel economy. Age and condition of the vehicle also matters.
Had a Yaris (1.3 Auto, non JDM), was a great car, never had any trouble but fuel consumption would be 10-11 km/l on average like Crosswind mentioned, though manual gear version will be slightly better. Got a new WagonR Safety (0 mileage, bought from Japan) and the most disappointed I'd ever been in a car. Considerably spacious for the size and good on fuel (depending on road/traffic conditions) but lack of luggage space and other engine/hybrid issues are making me want to go back to a Yaris. Sticking to a simpler car will make your life easier if this is your first/one of the first cars.
