Stepping up to a midsized sedan brings more interior and cargo space. Redesigned for 2009, this Mazda6 is roomier, quieter, and quicker than the generation it replaced. Teens will appreciate that it is relatively fun to drive, while parents will appreciate its more practical qualities including decent reliability. Bypass the V6 and get the 2.5-liter four-cylinder, which delivers better-than-average acceleration, while returning a decent 24 mpg overall.