On the Greek Islands we get familiar with the ferries as we island- hop the Aegean. Sun-drenched, upscale and exotic, Santorini sits on the rim of an ancient, but still active, volcano. At one end of the island, the archeological site at Akrotiri uncovers a city frozen in time by the volcano's eruption 3,600 years ago. The island of Naxos offers serenity, a low-keyed pace and bargain accommodations. Its massive marble quarries and kouros sculptures were the toast of ancient Greece. We catch some R&R on trendy Mykonos, and then head to sacred Delos-an uninhabited island covered entirely with ancient ruins, and the place where the great god Apollo was born. Tips: Discovering little off-the-beaten-path surprises.