I recommend you not only going to Iguaçu Falls in Brazil but also to the Argentinian park. You will have a breathtaking experience of watching and hearing the falls from different angles and perspectives. In the Brazilian Park, it is nice to do the Macuco Safari (to get close to the waterfalls by boat) and the Black Well Trail (a trail by bike and kayak). Besides seeing the waterfalls, it is also interesting to visit Itaipu Dam.There you can choose between visiting an animal and nature conservation project, a panoramic view of the Dam by a tour bus or a complete site tour (which I found very interesting) visiting all the installations inside Itaipu Dam. In the end of the day don’t miss the boat tour to watch the beautiful sunset over the lake dam (but make sure the sky is clear during that evening).
Another beautiful attraction is the Bird Park, where while walking along good walkways in the forest you will have the chance to see a lot of beautiful birds from all over the world, most of them rescued and treated on site.
As far as restaurants, I trully recommend El Quincho del Tio Querido and La Rueda, in Puerto Iguazu (Argentina). In Foz do Iguacu, two good churrascarias (meat restaurants) are Buffalo Branco and Rafain, where at night one can enjoy not only the good food, but also the show with typical dance and music from Brazil and other South American countries. Enjoy your stay and if necessary don’t hesitate to contact Loumar Tourism Agency, which I used and recommend. They can offer sightseeings to all important attractions in Brazil, Argentina and Paraguay.
If you haven’t booked your hotel yet, you can search here: http://www.booking.com/city/br/foz-do-iguacu.html?aid=1162245&no_rooms=1&group_adults=1