Hawaii is one of the most beautiful places on earth. Since Oahu is already wonderfully described in the first review, I can concentrate on the Big Island, Hawaii.
The Island has two quite different sides: East and West. The wind mostly comes from the West, so that is where the rains falls. Thus the West side is lush and green with rain forests, water falls, beautiful flowers and birds. The East is a black lava desert with wonderful beaches, some white (very white), some black, some even green (yes: green sand the colour of Hrithik Roshan’s eyes!).
Everything is worth seeing: the rain forests ( there are no snakes on Hawaii), the beaches, the coffee plantation (Kona coffee really is the best coffee in the world), the great volcanos, the saddle road ( huge fun driving there, like a roller coaster), Hilo (the cute capitel), the cliffs (major sport of the inhabitants: jumping down from somewhere), everything.
The people there are very helpful and friendly. Sometimes you get the impression they wait all day for tourists, so that they can be nice to them.
By all means: Go there!