Where ever you go it will be fantastic. We LOVE Hawaii.
Our favorite is Maui. We usually stay in Ka'anapoli or Kapula and we spend a lot of time in La'hania. La'hania has a great luau (book early), we love to go out on the little dingy's to whale watch....the whales get amazingly close and are such a sight to see. We are usually there in March for Spring Break... I am not sure of the time frame when the whales are coming through. Shopping is good in La'hania.
We fly direct shot from DFW to Maui (American Air), usually save up points to upgrade to first class both ways (worth it, believe me!!), we take the 10pm flight direct back to DFW, sleep and arrive around 5::30am.
Since it is a long trip, we do book Allen Limo (town car) to take us to the airport and then on the way home, when you are tired and sleepy, they are there at baggage to get bags and take you home. Worth the $$.
Have a great time, Hawaii is wonderful, I always hate leaving there but I love my home in TX.