The Materialist writes: 

"Ah, shave (not shaved) ice: The Materialist's favorite treat, and the first thing she gets after landing in her hometown of Honolulu. Locals can argue for hours about their favorite ice: Is it better super-slushy or a little coarse? Saturated with syrup or a touch on the dry side, so the juice at the end is a well-earned surprise?  (The Materialist likes hers tightly packed, with a snowball-like consistency, but icy enough to hold up under great lashings of syrup). Here are the Materialist's favorite shave-ice stands on Oahu:

1) Keneke's: A ramshackle wood shed on the way out to one of the Materialist's favorite beaches, Waimanalo, Keneke's not only has the best plate lunches -- that Hawaiian fast-food combination of two scoops of white rice, a scoop of macaroni salad, and protein (the Materialist likes the fried mahimahi) -- but superlative shave ice: a softball-sized heap of lovely icy white, all drenched in syrup. The Materialist had to stop going here for moral reasons, however: Keneke's is today covered with such viciously anti-gay posters and fliers that it makes even their transcendent shave ice taste rancid.

2) Waiola: No such ethical problems -- nor, unfortunately, the excitement -- at Waiola's. Still, this is a can't-miss post-beach pitstop and a good place to find all sorts of locals, from businessmen taking a quick "coffee" break to schoolkids on their way home. The best is watching some huge, tough-looking guy drive up in his Hummer, stalk up to the window, and depart a few minutes later licking a bright-pink guava ice. Spring for a scoop of vanilla ice cream on the bottom.

3) Matsumoto Shave Ice: This Haleiwa institution promises "the best shave ice in Hawaii," and, while it's a little too fine-grained for the Materialist, it has many, many fans, both locals and tourists. The lines are long, but it's practically a must-have after a long swim in Waimea Bay or at Shark's Fin Cove.

The Materialist's best suggestion?  Have all three. And remember what the Materialist's father taught her: Strawberry is the first true test of a good shave ice. If the stand can't make a good strawberry shave, it'll never be able to make any good shave."

Now, AGupta, I haven't forgotten that you're headed to Kauai, Maui, and the Big Island, so I also forwarded your question to Betty Cox of Travel Concepts in Fountain Valley, CA.  Betty is one of the Hawaii specialists on my list of the country's best travel planners. Her recommendations:

"The best shave ice on Kauai is at Jo-Jo's Clubhouse out by the Waimea Canyon on Highway 50. A good option on Maui is the Maui Espresso & Shave Ice in Kihei. As for the Big Island, all the farmers' markets have shave ice stands -- such as the Ali'i Gardens Marketplace 2 miles south of the Kona Pier. There is also Tropical Island Flavors in the Lanihau Shopping Center, and in downtown Kona there is always a line at (the strangely named) Scandinavian Shave Ice. In Hilo on one of our motorcycle rides we stopped at Itsu's Fishing Supplies and had a macadamia nut ice cream with rainbow shave ice on top!  Yummy!"

Okay, now I'm drooling. And dreaming about how to finagle an assignment in the Aloha State.