Island tour

If you come to Roatan, it's worth your while to put aside a day to explore around the island. A lot of divers plan this for the last day of their trip, when they can't be diving anyway.
It's best to either rent out a car, or negotiate a price with a taxi driver to take you around, as public transportation isn't very regular farther east on the island.
I usually drive all the way east, and then work my way back to the west. There are some beautiful views on the way! I would drive at least as far as Marble Hill Farms- it's fairly east, past Punta Gorda. Here they make jams from all sorts of tropical fruits, and they'll put out an assortment for you to sample. They're not cheap, but they make a nice souvenir.
Punta Gorda is a Garifuna village. Not that much to see here, but lots of kids who love it if you have some candy along!
Oakridge is one of my favourite stops. It's a little community with all the houses built on stilts over the water. As you enter, you'll have people ask if you want a mangrove tour. You can negotiate a price, and have a boat ride through the canals that go through all the mangroves (they say pirates used to use these canals). The next town over, Jonesville, as a little bar/restaurant that can only be accessed by boat, so you can ask the boat driver to include it on the tour, and stop by for a beer.
French Key is home to the Iguana Farm (check the review on that for more details).
French Harbour is a fishing town, and has a great grocery store called Eldons, which has a lot of things you can't get at the other grocery stores. And then just a little further is the mall that has a bakery, the only source of fresh bagels on the island.
Pass by Coxen Hole (traffic tends to get congested, if you want to look around, I'd come back another day in a cab- there's a few gift shops, banks, grocery store, nothing too exciting), and head to Sandy Bay. Anthony's Key has IMS (Institute of Marine Science), where you can pay to swim or dive with dolphins, and they also have a free dolphin show most days at 4. Just west of Anthony's Key, on the other side of the road, is the Caramola Botanical Gardens: it's worth a few hours of your time, so you might want to come back there if it's getting late in the day.
Since you have transportation, you may want to head over to West Bay for the sunset and find a spot for dinner before heading home.