I had another look on your list, because I couldn't believe my eyes ...... I don't think you mentioned CRETE! A wonderful island with enough sights to keep you busy for over a fortnight, nightlife of many diverse types and wonderful beaches. For the ultra fit, there's the Samarian Gorge to tackle and for Sunday strollers, the Imbros Gorge comes highly recommended!

Car hire imperative - and away from the coast, the scenery is stunning and the real Crete is still waiting for you to enjoy it! STRONGLY recommended!

Symi, Paxos, Alonissos, Skopelos, Samos and Parga (mainland).

Kos is supposed to be real nice too, i havent been but know a few people who have

Spetses, hard to get there independently though.

Kos is very nice it is quite a small island but there is plenty to do. We hired a car and bikes while we were there and they were a great way of getting around rather than organized trips. We stayed in the resort of Tingaki which is quite nice with several bars and good tavernas it also had a couple of dance bars. There was a good sandy beach and buses that run into the town which is a must.
We have just recently come back from Santorini and to us was the best island we have been to as it is still quite traditional though very popular with Americans as they come of the cruise ships. The beaches aren't the best as they are volcanic but the rest of the island is fascinating. We stayed in the resort of Kamira which is the biggest resort on the island and more purpose built but we thoroughly enjoyed our stay here.

I agree with Alsacienne.... Crete !!!

It's a huge island with loads to see/do... beaches are very good, nightlife is lively in parts/chilled in others.

Just stay at the best place....Kefalonia!!!

Try the Pelion, spectacular scenery, great beaches and very Greek. Car hire essential.
Or for an island you could cover on foot Patmos. Theres a main town larger than you might expect with plenty of tavernas and again mainly Greek. Samos is another possibility, few more Brits here but no lager lout resorts and big enough to retain a Greek character in most of the villages