Well the best 2 tours were the Golden Circle and the southern coast, where you visit a volcano, some geysers and waterfalls, and the black sands beach. Seeing the Northern Lights was amazing and the whale watching boat trip where we saw dolphins was another highlight. We've learned to schedule a guided food tour as our first excursion, as those guides are usually well-versed on the nuances of local spots/issues. We were blown away by how delicious all the food was there, except for the shark... it's worth it for the experience, but hard for me to recommend as the taste is so powerful. The museums were well worth visiting!