The Official Recommendations:

A Neotropical Companion by John Kricher
An Environmental History of Latin America by Shawn William Miller
Field Guide to the Birds of Peru by Princeton University Press
Good binoculars, (ie: Nikon Monarch 10x42)
Cipro
Malaria Medication
Sunscreen
Toothbrush/toothpaste
Repellent with DEET 
Sleeping bag and a light sleepsack 
Field Pants (3 pr).  
City pants (1 pr) 
Towel
A couple of wraps of duct tape on the water bottle  
Headlamp 
T-shirts (at least 3) 
Underwear (3-pr) 
Wool Socks (3-5 pr)
Long-sleeve field shirts
Synthetic long underwear
Rain jacket 
Fleece pullover or jacket 
Camera and film or storage cards, extra batteries 
City shoes (tennis shoes or light hikers) 
Hiking boots 
Sandals or aqua shoes
Rubber boots (buy them there)
Hat
Extra money for personal purchases, going out, etc. 
Notebook for recording field observations. 
Pocket knife or Leatherman
Alarm clock

Our Additions:

Water resistant watch
Daypack
Plenty of underwear; polypro is great
A large duffle bag (wheels can be useful, but not essential)
Snacks (Trail mix, peanut butter cups, lance crackers, etc.)
Anti-itch cream
A journal that won't deteriorate in the rain/humidity (Rite in the Rain is a great choice)
Biodegradable soap
Moleskin for blisters
Tylenol/Ibuprofen
Band-aids
Chapstick
Hand sanitizer 
Hiking pants are a must; wet jeans are no fun
A good pair of hiking boots; you really don't want the soles to fall off...it happens
Hat
Extra pens; they are few and far between in the rainforest and essential for journaling, birding, everything.
DO NOT forget your hipper shirt for the city

The Clothes Make the Adventurer

The Look: Kim Possible

The Look: Hiram Bingham

Also, be sure to bring these professors...

Dr. Emily Wakild- History Professor. Without her, we would have never made it.

Dr. Miles Silman- Biology Professor. We're fairly certain he's the real Indiana Jones.

Precious.