Chickadee
In other news, there is a new documentation server for Chicken Scheme online. It’s called Chickadee and it looks pretty damn useful. You can look up built-in functions, SRFIs and eggs. I’m currently working on a little project that uses Chicken, so I guess I’ll be using this a lot. ^_^
IMHO, Chicken and Gauche are the two most desirable Scheme implementations at the moment. They both have a pragmatic approach that isn’t always present in other implementations. (Although I haven’t tried every single one of them…)