Back-up camera After a century of using a glass mirror to try and not hit things when backing up, rearview cameras are finally becoming common on cars. Essential on SUVs and vans, but also useful on sedans, the image from a back-up camera shows you what you can't see in the mirror: your rear bumper. Rearview cameras help prevent expensive property damage. But more importantly, they can keep you from backing over a person.
Blind spot warning Even if you are the most aware driver on the road, you won't notice a car changing lanes into your blind spot. And with C and D pillars getting wider in many car designs, those blind spots are getting bigger. Blind spot warning systems show a warning light on the sideview mirror when a car is sitting in your blind spot. When you look at the side mirror to see if it is safe to change lanes, it is very reassuring to have that extra set of eyes that see where you can't.
Navigation with traffic detouring Navigation systems are great and have become very common. But they are much, much more useful when they can tell you about bad traffic jams ahead, and suggest a detour. Not only do they help you avoid the frustration of being caught in a parking lot on the freeway, these systems help your pocketbook and the environment, as they keep you from getting stuck in situations of wasteful idling while waiting for a car accident, or other obstructions, to be cleared.
iPod or other MP3 player integration
We focus on iPod integration mainly because these music players have a majority market share. Automakers realize this, as well, and have been adding iPod integration into many models. Good iPod integration lets you plug in the device, then browse your music library on the car's LCD or radio display. You should be able to select music the same way you do on your iPod: by artist, album, genre, playlist, or track. An iPod beats leaving a stack of CDs on the passenger seat, and we even find it preferable to having music stored on a hard disk in the car.
Bluetooth phone integration with dial-by-name voice command
Many cars have Bluetooth phone integration these days, a very useful feature with more states banning handheld cell phone use while driving. But most of these systems are useful when people call you. A few companies--Ford, Kia, and Lexus so far--not only have the Bluetooth system copy your phone's contact list, but also include voice command that lets you place a call by saying a name in that contact list. Because face it, how many actual phone numbers do you have memorized?
Hybrid power trains
Although it didn't make the top 5, we give gas-electric hybrid power trains an honorable mention here because they offer the best of both worlds: more power and better fuel economy. Just compare the Lexus RX 450h with the Lexus RX 350. The hybrid system achieves this seeming miracle by collecting energy from braking and excess engine power that would otherwise be wasted, and making it available to drive the car's wheels.