My wife and I went to Kauai last year with my wife (10 year annniversary).
For an awesome experience, take a trip up the Na Pali coast with Catamaran Kahanu. Father / son hawaii team - excellent experience. Just tell the son that the guy who celebrated his 10 year anniversary last year sent ya! (Or, tell him I'm the guy who mis-pronounced the hawaian word for arm band -- I pronounced it 'balls' as is 'you gotta have balls to sky dive' instead.

)