here's donna rosato, senior writer at "money magazine." >> got a good credit score? you do if you've got a score of 740 or higher. just one third of americans are members of that elite club. if you're one, you already know that a good credit rating will nab you the lowest rates on a home or auto loan. but it also gets you access to some pretty good deals elsewhere too. credit cards have notoriously high rates, averaging more than 14%. but many credit card issuers seek out top credit score holders by offering significantly lower rates and lucrative cash-back deals. having a high credit score will also give you more leverage negotiating a car purchase. car dealers make the most on financing. dealers are typically locked into preset rates, but if you say you can get a better loan deal elsewhere, you may be able to knock a few hundred dollars off the car's sticker price. a good credit score can also make the difference when you're applying for a rental apartment or a vacation home. a solid credit score is a sign that you'll be a responsible tenant and gives you room to n