Again riadh, it would help us give better advice if you'd give at least the approximate dates of travel... is there any objection to this? (Are you in a Witness Protection Program he he he). If you are thinking of going late August through mid-September, you'll be OK as far as crowds, the huge throngs do tend to depart to get their kids back into school. As for the islands you mention, you can find out SO much about their attractions by checking a GOOD guidebook -- I do not have any idea where you live, since you share so little about yourself, are you in a nearby country, an English-speaking country... what??? IF you're near a good library, the ROUGH GUIDE is the best/quickest place to give CANDID answers about an island's appeal AND drawbacks (which are never mentioned in online promotional websites).
You ask : "Naxos and Ios: Are these the islands where i can find: • Beautiful villages • Good nighlife •Local festivities festivals & traditional music • tasty food • Cultural and archeological curiosities,? My comments, on these & others:
• NAXOS - Has ALL of these! After SEpt 1 suggest staying in St. George Beach area because clubs r mainly in the attached Port Town & its so easy to stroll back to hotel late; this SkyMap http://www.skymap.gr/apps/site/viewmap/?mapid=29&cid=305 clearly shows how beach & town interconnect; otherwise, look at Ag. Prokopios IF you can get hotel on beach (LIana hotel is one such). Naxos has wine festivals in early sept, has weekly concerts of traditional Greek music/dance, MANY ancient sites!!!
• IOS - In July-August, is mainly a college fratboy party island; do you like beerkeg parties? Off season, quieter. Beaches fine, no ancient sites of interest
• TINOS - thru Aug 15-20, mainly a huge religious-visit mecca ... and never has much nightlife at all. Friends had a house there and "commuted" 30 mins to Mykonos for business & social life. Its mainly noted for small villages where women do embroidery, and lots of dovecotes, all over. I've never been attracted to either tablecloths or pigeons, so I've skipped Tinos so far.
• PAROS - ANTIPAROS -- Paros has much of interest, but as a place to stay, I enjoy Antiparos so much!! And you may have your cake & eat it too! The strategy would be to stay in Antiparos, right near the tiny port (Mikes Place or Sunday Hotel), and day-trip to Paros to explore Parikia, bus up to Naoussa ... then back on Antiparos, enjoy easy walks to sandy beaches & lovely sunsets.
OTHER CYCLADES - Again, your stinginess with facts is frustrating! You say "My problem is that i visited most of the cyclades" -- but which ones??? Have you been to Milos, Sifnos, Serifos, Amorgos, Folegandros -- I have visited all these and have info on both their attractions & drawbacks, but am not going to bother to describe, if you then say "been there, done that." If you want the BEST advice, you need to give BETTER information.
SPORADES - Again, research can help you decide. Both the guidebooks AND forums like Trip Advisor let us know that your experience can be very mixed; Skiathos is very much a British-holidaymaker "hive" with charter flights and package-vacation crowds - Skopelos & Skyros much less so, because harder to reach -- however, I'm not sure how much in way of ancient sites, and local festivals you'll encounter on either. You MIGHT consider going to Chalki and to SAMOS (in the latter, avoiding the big UK package-holiday centers at Pythagoras etc), Western Samos adored by hikers, great landscapes. Again, you'd need to do quick in-depth research to decide ... both plane tickets and accommodations easier to come by in Samos, Chios and NON-airport Sporades.
Please realize that you are asking a lot at a very late date, and without sufficient facts we may waste our time in trying to develop scenarios for you that are not appropriate ... do fill in the facts, and prepare to act FAST on any bookings advice. Good Luck!