Over the next few months, Japanese automaker Nissan plans to introduce several big changes to its lineup of vehicles. As older models are replaced by new ones, drivers can expect previous vehicles to hit the used car lot at a discount.

Nissan's new ad campaign promises "innovation for all," and the company is putting its money where its mouth is by unveiling several brand-new or redesigned models before the end of the year.

The most visible of these will obviously be the highly-anticipated Leaf, which will be one of the first all-electric vehicles to go into mass production. The Leaf will be available in several markets in December before slowly rolling out nationwide in 2011. Demand is already high for the vehicle with the company already surpassing its sales totals. It's due to go head to head with the Chevy Volt, but the Leaf holds a key advantage (or possibly a disadvantage) over the Volt in that it only contains an electric motor compared to the Volt's electric-gas hybrid engine.

Another model sure to turn heads is the new Murano CrossCabriolet, which the company is touting as the first convertible crossover. Early impressions have been polarizing, with some loving the bold choice to offer a convertible on an SUV-like vehicle and others liking the idea less. Nissan itself has admitted that it doesn't expect the car to sell well compared to the regular Murano, but hopes that the design will call attention to its new marketing strategy as an innovator.

The brand-new Juke crossover is another new car that may benefit from Nissan's aggressive styling. Unlike other cars in the compact crossover class, the Juke achieves a coupe-like design by using sharp angles to immediately catch the eye. The vehicle is powered by a newly-designed 1.6-liter direct-injection turbo engine that produces 188 horsepower and 177 lb-ft of torque.

The last new model is the redesigned Quest minivan, and while this design won't turn heads like the new Murano or Juke, it got the attention of some insiders simply for being a minivan. As other automakers move away from this segment and parents move toward crossovers and SUVs, Nissan is banking on the dwindling minivan market to fall in love with the redesigned Quest. Previous versions of the van weren't as popular as competitors' models, so Nissan is hoping the new model will lure buyers back.

With so many new models set to debut before the end of the year and even more slated for 2011, buyers who are in the market for a car may want to hold off and wait for a used Nissan, as many of the older models will likely be able to be found at a discount compared to their current price.