Go to the airport early!!! If the Lan Chile flight originates in Tahiti, they will fill the plane with passengers and only leave a few seats empty for Easter Island. This is because the Tahiti airfare is higher. If you don't go to the airport early, other passengers who check in earlier will get the few remaining seats. A couple from Italy had to stay in Easter Island for several more days because they arrived at the airport only about 90 minutes ahead of time! Few places in the world must you fight to get home! //// Another warning is that in March, 2002 the only case of dengue fever, which is transmitted by mosquito, was reported in Chile in a woman who had lived in Easter Island for 2 months. Further investigation showed that at least a dozen people had signs of previous dengue fever. (In comparison, Cuba and Brazil report tens of thousands of cases of dengue fever)
Bring a hat that's good for wind, sun, and rain. Bring sunscreen (remember that article? Pack sunscreen.).
If you go out anywhere on the island, bring LOTS of water and more food than you think you need. There's no water or stores except in town.
There are many nasty mosquitoes. I had a bit of an allergic reaction to them (bites swelled; rash on arms and back), but nobody else did. Watch for black widow spiders in the rocks.