Hi there, spent Christmas in Hawaii two years running, absolutely loved it.
Honolulu is great, but more commercial. Clean and safe, Waikiki beach does the trick and February should not be terribly busy. Food options are great so are restaurant and bar options, you must go for lunch on the veranda of the Moana Hotel (a beautiful old colonial hotel on Waikiki beach) equally cocktails at the Royal Hawaiian hotel otherwise known as the Pink Palace. The first five start hotel in Hawaii, built in the 20s and frequented by the likes of Charlie Chaplin, Douglas Fairbanks and the Hollywood elite of the era. The best hotel in Honolulu is the Halekulani, which is amazing but as was stayed for just over one month on both ocassions I ended up staying at the Ohana West Hotel, part of the locally owned Ohana chain, good value for money and fantastically well located. As already adviced by other used of the site, you should visit the North Shore, and Hanama Bay.
With regards to Maui, is is beautiful and less commercial. Go to Big Beach (stunning never ending beach), Lahaina (which used to be the old capital of Maui) great seafoood reastaurants in old colonial buildings built on stilts and make sure you get a table for early dinner to withness amazing sunsets. And if you have time drive the Road to Hana, all 40 kms of it. Winding roads, dangerous at times and do make stops along the way to see the stunning waterfalls en-route. When you arrive in Hana (which is more hamlet than village), go to visit Red Beach (literraly terracota coloured sand like I have never seen in my life), you need to go past the grounds of a hotel (cannot remmember the name), through a japanese prisoner of war cemetary (spooky!) and the through a little path on the side of the mountain to see stunning beautiful cove which is wild and peaceful, the colours and the wilderness are well worth the visit (make sure you buy food for a little snack from Hana's only convenience store).
Enjoy Hawaii and don't worry if you can't fit everything into the schedule as it will always give you an excuse to go back, at least that was my excuse!