I wouldn't say we've finalized our input bindings yet, but even so, I can say that for a mouse and keys player, combat is mostly a combination of wasd for movement, mouse movement for camera/look control and turning, and your left and right mouse buttons for using the weapons/items in your hands. There might be a few other keys that come into the way you play as well (the number keys above the letter keys, for example, can be used to quickly use easily accessible items in your inventory that you bind them to.), but those are the core controls.
It's definitely not a "hotbar" combat system in the Everquest or World of Warcraft sense, but is instead more of an action rpg sort of experience. It plays pretty well on the gamepad too, as a result.
Hope that helps! :)