I stayed at Chaa Creek while I was there, really nice place and you are right in the midst of wildlife. Great food, comfortable beds and plenty of activities such as horseback riding, canoing, mayan farming, nature walk, they even have a thing called creatures of the night. They take you around and show you what is crawling around, very neat.
Here's a picture I took one morning. The sounds in that part of the world are amazing as well. http://www.richguy.com/pictures/belize/000247.htm
Let me know if you want more pictures, I can post them somewhere for you.