My Wife and I are planning a vacation to Hawaii this September, this will be our second visit as we visited Maui and Honolulu back in 2008. Last time we stayed at the Westin Kaanapali on Maui and loved it, we loved the island and the resort. This time around we are looking at either Kauai or the Big Island, my first question is how do they differ from Maui. On Maui during the day we we did surfing, biking, kayaking escursions or would lay around the pool/beach. Most nights we went to Lahaina to go to dinner and walk around checking out the shops. Are there similar places on the Big Island or Kauai, someplace similar to Lahaina to walk around, check the shops, have dinner at night which is not too far from the resort areas.

Second does anyone have any experiences with a resort they recommend? TripAdvisor's reviews are all over the place, here's what we've been looking at:

Big Island:

Hilton Waikoloa Village (property looks fatastic, reviews say it's dated?)
Fairmont Orchid
Waikoloa Marriot Resort


Kauai:

Grand Hyatt
St.Regis Princeville
Marriott Kauai resort
Sheraton Kauai resrt

Any other recommendations appreciated, around $300 or so per night would be the budget.

Thanks.