For a year I looked after a store on the IoW and visited at least weekly. It's an unusual place which like all small islands is rather incestuous (we used to joke both literally as well as metaphorically).

There is some stunning coastline to visit, both the railways are great fun if you like transport and the sailing season in Cowes is good fun as noted above. The other towns are highly missable. And don't visit out of season as it's pretty miserable in January.