If you're looking for a used car, be sure to look in the Kelly Blue Book prior to getting too far into your search. Utilising the Kelly Blue Book is a fantastic way for you to gauge how much you should pay for the car you're interested in.
Consumer studies and Car and Driver will tell you much of what you need to know about a car's reliability. These two magazines give you tons of useful info about used cars?life expectancy, maintenance costs, and?point by point?which systems of the car (e.g. transmission, engine) are likely to need to be repaired or replaced, and which may not.
Be warned that there are a few significant things the Kelly Blue Book isn't much good for. It doesn't provide any indication of how dependable a car is, or how problematic it may be. You can get some indication of this by gauging how well the car retains its value, but Kelly Blue Book will mostly tell you pricing
I also like epinions.com. You'll locate a wide range of information about almost every car that's ever been made, written by real people. All of these sources are excellant because of their thoroughness and objectiveness.
Of course, none of these are enough. The Kelly Blue Book will explain how much to pay, and Consumer Reports, Car and Driver and epinion will give you strengths and weaknesses of the cars you're interested in. But we also suggest getting the car examined by a mechanic you trust. And trust yourself to spot problems on the test drive, even if you don't know much about cars.