Hi, i just got back from Greece on June 16, 2007 was there for 2weeks.
All islands were great.
DO NOT book speed boat/ferry called Super Jet to the islands. Super Jet kept breaking down and didn't even show up for our trip to Mykonos... (even the travel agents their told us not to book it) it's not reliable and you will lose your ticket and money and have to buy another ticket. (you can only get your $$ back for the ticket if you go to the same travel agent you bought it from)
Use the Flying Cat 4 / vodafone... that one was the best and most reliable fast boat. Book your ferries to each island when you get there... it's the same thing, you can go to any travel agent there.
Loved all the islands... have a blast and safe trip.