[eluser]theprodigy[/eluser]
I collect it in the controller, myself. That way, the controller decides what gets sent to what model. You may have a form that needs to access several models for either a select query, insert query, etc. The controller will take the form submission, then send the correct data to the correct model.
You can also use the controller to validate and/or modify the submitted data prior to sending it to the model.