I'd heard that Iguaçu National Park in Brazil offered the best views of Iguazu Falls, and the park did not disappoint. All visitors must ride a bus from the park entrance to the trails serving the falls, and I rather enjoyed the view of the rainforest from the top deck. Once I arrived at the main trail, I was immediately captivated by the view of the Argentine falls near the boat dock. From the Brazilian side you can walk for somewhere between one and two kilometers and not run out of awesome waterfall views, which was the biggest surprise for me. At the end of the trail a boardwalk leading out to the Devil's Throat, a narrow U-shaped set of waterfalls, provides visitors with the best opportunity to get soaked by the spray from the falls (although vendors would be more than happy to sell you a poncho). A tower near the boardwalk also offers a panoramic view that's worth seeing. Iguazu Falls was as spectacular as I'd imagined, and I'm glad I took the time to see them from the Brazilian park when I visited in March of this year.
Logistics: Iguaçu National Park is accessible by car or bus from both Foz de Iguaçu in Brazil and Puerto Iguazú in Argentina.