Jump City is great for the intermediate Kite Boarders giving some great launches. Excellent for wave riding and jumping. Diamond Head has waves year-round with peak months during the summer. Most local sailors use a 5.2 or 5.0 sq. If you come during spring, however, you will probably need a smaller sail.
Naish boards are all over the beach.
The North Shore of Oahu has extreme wavesailing conditions from October until May. Oahu's North Shore provides some of the best wave riding conditions in the world. It's an hour's drive from Kailua. Mokuleia is a very popular spot for the Intermediate - Advanced kiteboarders. Kailua Beach in the Winter Winter conditions in Kailua are varible from light trades and calm water to strong north wind and big waves out at the reef.