Freshwater is nice and quiet not much to do, but a nice beach.
If you have DC Blackgang Chine is a must, it's a theme park type thing, but not really a theme park.
Robin Hill is also good for the DC, owned by the same people, if you go to Blackgang you get free entry to Robin Hill if you go within a week.
Shanklin has nice beaches and lovely walks, lots of tea rooms and pubs right on the beach.
Ventnor again nice beaches.
The Needles has a small fairground and a chairlift down the cliff to the beach. Children will probably enjoy it.
Newport is the best place to do some shopping, but it's not big.
When you get on the ferry, look out for a visitors guide, it tells you the good pubs and restaurants.
Have fun. Weather has been nice down here for the past couple of days and is supposed to stay good for a while.