One of the mysteries of world travel is that it is often very hard to get a good map once you're in the country you're visiting. Greece is no exception, so find your roadmaps first - and you'll also have more fun planning your trip.
This Greek company prides itself on double-checking its facts, making its modern maps possibly the most reliable available for Greece. You can't find them through most of the on-line services, so either go through their web site or keep an eye out for them when you're in Greece - the Athens Airport newsstands will have most of them.
Handy traveler-friendly map of Athens, the capital of Greece.
Choose from a selection of maps of Greece, including laminated maps, political maps, and streetmaps of Athens.
Maps on individual areas in Greece are even harder to find once you're there (though the bookshops in Matala, Crete and Piraeus carry a good selection). If you're Crete-bound, pick this one up first.
Once again, a good map is hard to find. Take this one with you. Published in 2003; road changes made just before the Olympic Games in 2004 may not be indicated.
Good overall map of most of the major Greek islands. Comes in a laminated "Flexi" form also.
Rhodes is another island with reasonably tourist-friendly roads - so this is a map you'll find very useful.
Choose from these maps of Corfu to guide you around the popular Greek island.
From the renowned French company, a handy map of Greece (in English).