Lipsi (Λειψοί)
A lovely small, laid back island with few tourists when we first visited in 2002. Still very quiet but with a few more facilities now. Still very attractive, with some nice quiet beaches.
Lipsi is a great place to get away from it all but if you really want to take that to the extreme take a boat trip to the neighbouring islands of Marathi or Arki. Marathi has a population of 3 (a few more in the summer), no roads, towns or cars. Just a beach, a few houses, a couple of tavernas and a handful rooms to rent.