I do like the storage space provided by a kitchen island, but a harvest table allows one to show off a gorgeous table. It also provides a nice showcase for an eclectic chair collection (Mandy, are you listening?). They can make a crowded kitchen more airy and light, plus you can move them out of the way to create an impromptu dancefloor!
Here's a nice example from Apartment Therapy. This is from Jeanine's house in Wellesley. She's applying for AT Boston and I really like her digs. And her chairs.