We love cocoa beach. There aren't many tourist attractions, but it is a nice, clean beach with great waves. Last summer we saw dolphins from the beach. They were way out there, but it was still a pretty sight. I like watching the big ships come into port too. I don't really see the appeal of RonJon's, it is just another gift shop. They recently opened a water park though, and I haven't been to that.
If you have time, I highly recommend a dolphin tour of the Indian river. It is just a nice, relaxing, scenic boat ride. The guide will give you a history of the area and you'll get to see wildlife up close and personal.
For a nice meal we love the Fat Snook. Pricey, but well worth every penny. DH loves Florida Seafood, I am not a big fan of them though. Madd Jack's Grillin Shack makes awesome BBQ. I would avoid The Mango Tree at all costs. It use to be the best place in Cocoa Beach, but it changed ownership, and it is terrible now.