The only Greek island i've been to is Crete. Crete is the biggest and most southern of the Greek islands. It's about 260 KM in length and between 12 and 60 KM width.
Nowadays the island is populair for youngsters who like to go to the beach during the daytime and party at night. But the island offers a lot more then just that.
Chersonisos is one of the most populair places on the island, and if you like to party, this is the place to be. The beaches are not the best though. They are small and crowded and some places have a lot of rocks in the water. If you want a nicer beach then you'd better take a bus in the direction of Malia.
I'll need to scan some pictures, so give me a few days to add some intresting places.