Isola Bella, one of the 3 Borromean Islands in Lake maggiore, has a Palace, impressive formal Italian gardens and tourist shops and restaurants too but it does get very crowded so I would recommend visiting early in the day. If you are interested in grand houses and their contents then get on a tour or rent an audio guide. We enjoyed our time there but preferred the tranquility of Isola Madre.
The islands are all served by frequent boat services from Stresa and all 3 islands can be visited in one day on a discounted ticket from the 'official' boat service. There are many other smaller boats offering the ferry service but, as the salesmen were so pushy, we avoided those so we never did find out which offers the best deal!!