I'm planning a vacation to the Hawaiian islands in next month. Anyone have suggestions?

I would recommend breaking your vacation into two. Spend one week on one island, and end with a trip to Maui. Since you mention the volcano specifically, that means the Big Island. We stayed on the very south point of the island of Hawaii. It was a beautiful, windy place with huge wind farms and a beach where the sand was soft and green. It was a short jaunt from the lava too. We did not like Hilo very much, it seemed tired and run down. Kona seems pricey and crowded. Maui was wonderful, it has everything. Bike down the volcano, you will go through all the world's climates from the Scottish highlands to a tropical jungle. East Maui (whichever side of the two mountains that faces the wind) is wet and tropical, West Maui (the sides of the two mountains in the lee of the wind) is dry and warm. Kihei and Kaanapali have a climate that has been compared to Arizona. Do take time to read recent reviews on where you stay. If you are renting a condo, pay particular attention. If you rent through a management agency like Outrigger or Aston, they have quality control standards that the properties that they manage must meet. They need to be clean and in good shape, or they don't get customers! There is a minority of condos that are rentals by-owner that are not so nice... and many that are very nice. Hotels and resorts are more straightforward. Also, be sure to book your activities in advance. You can often get a discount if you book two things at once, such as a discount on a guided hike and a sunset dinner cruise. Maui even has submarine rides. I have two sources. Have fun, and no pressure. There really is no 'wrong' place to stay on the islands.