The Best

Toucan Guides Waterproof Travel Map—After more than a decade of travel around Costa Rica we were frustrated with out of date low quality maps that showed a quarter of the roads and dissolved in the rain so we created the Toucan Guides Waterproof Travel Map. Order $9.95, 2005, ISBN: 0976373300—Details

The Good

Bernston & Berston Verlag—Not a bad choice if you're sticking to the main roads.  Printed on coated paper for water resistance. Order $10.95, 2005, ISBN: 3866095104—Details

National Geographic Adventure Map—As you'd expect the folks at National Geographic have done an excellent job with the geography, unfortunately the title "Adventure Map" is something of a misnomer and many people also find the format with half the country on each side of the map quite annoying. Order  $9.95, 2004, ISBN 1566951755—Details

The Rest

Insight Fleximap Plus Travel Information—is the cheapest map of Costa Rica you can buy and there are a lot of good reasons for that. $7.95, 2004, ISBN: 9814137685—Details

ITMB Costa Rica—Although the copyright is just two years old (2004), it appears that this is simply a reprint date, and the map has not been updated for significantly longer. $9.95, 2004, ISBN: 1553411803—Details

The map you get for free from your rental car agency.  In most cases you get what you pay for, sometimes a little more and they aren't too bad as long as you don't leave the main highways and don't get the map wet.  If you're going to rely on the map in the glove box (assuming there is one) you may also want to download and print the Toucan Guides free map of Costa Rica.  It only has the main routes, but at least they're current.