I'll try to make this site better continually. Author A few more bits of information. I think I don't need to describe an importance of a brake system, so, pay attention to check it. Don't forget to check parking stop. It's not so useless thing as it seems.
Some cars have disk brakes at the front and drum brakes at the rear.
Others cars have disk brakes at both - front and rear wheels. Disk brakes have better efficiency, therefore cars with disk brakes at all four wheels are preferably. It's quite useful thing, especially if you live in area, where slippery roads are common. However, ABS is quite complicated device and breaks sometimes - so, if a car you are looking at have it, you need to check it. If this guide too complicated for you, I also have How to check a car - simplified guide.