It'd depend on your budget. If you're looking at used cars, the Ford Fiesta arguably provides the best balance between driving fun and practicality. You can no longer buy one new, however. The various iterations of the Mini hatchback are even more fun, but you're sacrificing boot capacity and interior space by choosing one. Another option could be the Peugeot 208, if you're happy with the atypical 'i-Cockpit' driving position.