I would recommend different islands depending on your preference, hobbies and what your likes and dislikes are. If your young and like to party and go to a busy island like Oaho. There was lots to do and I did things like sport fishing and enjoyed the night life. I have recently been to Kauai and really liked the hiking, snorkel and scuba. The island is more quiet but really geared more for the outdoor enthusiast because most places closed early but opened early. Lots of films were filmed there because of the beautiful scenery.
Check out
http://www.gohawaii.com/.
Westjet directly flys to most of the islands. I think it cost about a hundred bucks to fly between islands and there are cruises as well.