St Catherine’s Point Lighthouse and the Buddle Inn, on the southern tip of the island, is a great walk/pub/attraction combo.
Likewise, parking in Yarmouth, walking along the Yar estuary to Freshwater and having lunch at the Red Lion, and walking back to Yarmouth.
The falconry thing at Appledurcombe House in Wroxall is pretty good, if you like that sort of thing.
The walk from Tennyson Down up to the The Needles Old Battery and back from Freshwater Bay is pretty interesting, great views and interesting history around the old abandoned rocket site.
Steephill Cove and Ventnor Botanic Gardens are all very picturesque and an easy walk if you park in Ventnor. The Spyglass Inn is a good pub round there, full of nautical bric a brac and with a great location at one end of Ventnor beach.
IsleofWightseakayaking.co.uk are good if you fancy trying kayaking – great location on Freshwater Bay.
Shanklin Chine, a raving with its own subtropical microclimate, is pretty cool, as is Shanklin in an old-fashioned bucket-and-spade seaside resort sort of way.