Do you like walking? Head out to the West Wight, park up at Alum Bay (you can park up before the official car park, where you have to pay) and walk out to the Needles Old Battery. You can walk around the south side of the hill, where the rocket testing site was, then you can walk up on the hill (known as a Down). Keep walking along and you'll get to Tennyson's Monument, which has some stunning views.
Coast on Cowes High Street will give you a good lunch, or if you want to push the boat out go to the Pond Cafe in Bonchurch.
Are you just over for a day trip, or what?