1. BMW M6

19% drop in residual value

Analysts blame tough competition, fickle buyers and the recession for the BMW M6's huge drop in value. With a V10 engine that could just as easily be in a race car, and a sweet steering and suspension setup, it's an absolute riot to drive. But flashier models like the Audi R8 have drawn attention away from the M6, which has hardly changed since being introduced in 2006. Its $102,350 base price puts it in Porsche territory, too. Furthermore, the recession has seriously eroded sports-car values in general. "This is kind of like the $2 million house at the end of the street," says IRN's Schneiter. "It's great, but I would expect it to sit on the market a little bit longer than most."

Compare: BMW M6 vs. Porsche 911 vs. Audi R8

2. Land Rover Range Rover

Click to enlarge picture2010 Land Rover Range Rover (© Land Rover)

2010 Land Rover Range Rover

19% drop in residual value

The Land Rover Range Rover hasn't had a major redesign since 2003, and this really hurts its residual value. Making things worse, the Range Rover is expensive, with a starting price of $79,275, which means it will lose more value over time than other models that cost less. Rounding out a triple threat to its residual value is Land Rover's consistently poor quality and reliability. The brand ranked second to last in the most recent J.D. Power Initial Quality Study and has been at the bottom of that list for years. India-based Tata Motors bought the brand in 2008. "During this down economy, they [Land Rover] really haven't been able to generate the cash flow and put the investment into generating next-generation designs," Schneiter says.

Compare: Land Rover Range Rover vs. Lexus LX 570 vs. Cadillac Escalade

3. Mercedes-Benz G-Class

Click to enlarge picture2010 Mercedes-Benz G-Class (© Mercedes-Benz USA)

2010 Mercedes-Benz G-Class

18% drop in residual value

The Mercedes-Benz G-Class — not to be confused with the newer GL-Class — is part of a niche within a niche that has many things working against it. Not only is it a large luxury SUV, it's a rare one that costs way more than even a Land Rover Range Rover — starting at $104,000. On top of that, it's an acquired taste. The G-Class is based on an overbuilt military vehicle designed to ford streams, climb dunes and withstand gunfire. Mercedes says that in 2006, a G-Class was driven more than 11,806 miles on a trip through Siberia, in temperatures as low as minus 63 degrees, without a single breakdown. People just don't need that kind of performance in the suburbs. And the few rich folks who previously might have considered buying one of these 6-figure SUVs to show off have moved on to something that gets more than 13 mpg, weighs less than 5,622 pounds and was designed more recently than the 1970s.

Compare: Mercedes G550 vs. Land Rover Range Rover vs. Porsche Cayenne

4. Mitsubishi Galant

Click to enlarge picture2010 Mitsubishi Galant  (© Mitsubishi)

2010 Mitsubishi Galant

17% drop in residual value

The Mitsubishi Galant was last redesigned in 2004. Like the other vehicles in the bottom five for residual values, this midsize sedan suffers because it has become outdated. It's a competent performer with a comfortable, spacious interior and a decent ride. But put it next to a Ford Fusion, Honda Accord, Nissan Altima or Toyota Camry, and rough edges start to show. Even with its value pricing, the Galant comes up short in a competitive field with gaffes such as cheap materials inside and an unrefined powertrain. Like Land Rover, Mitsubishi is in the unfortunate position of not having the financial wherewithal to invest in upgrading its products, Schneiter says. Hence the big dip in residual value.

Compare: Mitsubishi Galant vs. Ford Fusion vs. Nissan Altima

5. Hyundai Azera

Click to enlarge picture2011 Hyundai Azera (© Hyundai Motor America)

2011 Hyundai Azera

17% drop in residual value

This Korean sedan with premium features was a compelling choice when it came out in 2006. Its high quality, long list of amenities and affordable price earned it a spot on our recent list of most underrated rides. But Hyundai now has a new premium sedan, the Genesis, that upstages the staid Azera; likewise the recently launched all-new Sonata. "The Azera is actually slotted kind of in between those two, and it would definitely decline because, to tell you the truth, it is a little outdated," Schneiter says. But if you plan on keeping it forever, rather than trying to resell it in a few years, there's still a lot to like about it.

Video: Hyundai Azera Review

Matthew de Paula wanted to be an automotive journalist ever since reading his first car magazine in grade school. After a brief stint writing about finance, he helped launch and became the site's editor in 2006. Matthew now freelances for various outlets.