Just wanted to share one of the best spot I've found. Having been travelling lately, one of the greatest kitesurf spot I found was in Fiji. Ellington wharf and the closest island Nanaru-I-ra offer all the way from March to end of the year a wind blowing between 15 and 25 knotts, up to 35 on very windy days! Great wind, flat water (coldest 24 degrees!) or waves (great surfing place too), possibility to do kitesafaris, amazingly beautiful place, lovely people, the best kitesurfing spot I've tried so far!!!
You can find more info on:
Also very good wind: Red sea (Dahab and Safaga, wind nearly blowing all year long, best in Spring and Automn), Boracay in the Philippines is perfect to add kitesurfing and partying (mid-november to mid-january).
Enjoy your ride!