We honeymooned in Hawaii for 5 weeks in 2008. I honestly can't remember what the total cost was, but I can tell you we did it pretty frugally. We spent about 1 week on each of the 4 major islands. Accommodations were half camping and half hostels or similarly priced rooms. We did splurge on a luau in Maui, and booked a helicopter on the Big Island (lava!) but our reservation got "winded" out, and it was our last day on the island. Everything else was done on the cheap, and it was an amazing time. Car rentals were cheapest through AAA at the time, and we used Hawaiian Airlines for the inter-island flights.
BUT we weren't going for fancy cocktails, cruises, and cushy sleeping quarters. We were there for beauty, nature, and adventure. Moonbows (stupid name, neat phenomenon) and sunrises at Haleakala, long hikes to green beaches and snorkeling (no need for big boats and $100+ day tours, just grab your gear in Captain Cook and hike in from road) on the Big Island, breath taking waterfalls, canyons, and impossibly muddy trails in Kauai. That kind of thing. It was an amazing trip, if this type of stuff is up your alley.
These days, with kids, we find ourselves opting for the Caribbean. Shorter flight for us since we are on the East Coast. Turks and Caicos, specifically. But we don't do much there. Just laze around on the beach with the kids and cook simple meals in our rented beachfront condo. DH and I want to take the kids to Hawaii, but we actually want to do stuff there, so the kids have to be willing and able to appreciate it. (They are getting closer at 4 & 6, but I think another couple years would improve the experience for everyone.)
Also, Boarder definitely spent less than us for "nicer" accommodations, but I'm a travel hacking weenie. We did stay 1 or 2 nights in Hana at Waianapanapa State Park, which I think was $10-$15/night.