We always bring a pair of running shoes for the trails and a pair of Keen's or other water sandals for rafting or when things are wet. For the evening, anything goes.

This question generally leads to many responses with suggestions about specific brands, styles, and designs. However, without knowing what you intend to do and where you intend to do it, generalizations may not be helpful. Nonetheless, it's rainy in October and that means water and mud--depending on where you go. Some woodland hikes are more level than others, and flip-flops would be okay. Some involve more slippery climbing than hiking. Water shoes/sandals are good for rafting and can be worn for almost everything else. What do you plan to do in the evenings? There are really only two shoe *requirements* First, if you are going to be where ants are, some sort of covered shoe is preferable. When you go where there might be snakes, it's nice to have taller rubber boots. Rubber boots are often available on loan at lodges/resorts/hotels. Many areas have trails or pathways that are maintained and fairly easy to negotiate--many with stairs. Serious trekking with backpacks, etc. requires good boots with lots of support.

There are lots and lots of hints and tips though. Red mud on white shoes doesn't look good. You may want toe and/or heel protection. You may want more support and protection on the bottom of your feet than crocs will afford--especially when hiking over tree roots. Whereas some people will travel with shoes for every conceivable activity, most won't, and you will see almost everything everywhere.

Mostly, though, it's your personal preference and *comfort*.

For CA, I generally wear a pair of hiking boots on the plane (gortex best in rainy season, for me), and pack Keens and flip-flops. Sometimes I just wear Keens on the plane and pack flip-flops, if I want to go extra-light.