For me and the other two users I have working in '09 this setting does not matter. I've tried every combination of these settings that I can think of - do not save changes, automatically save changes, start on layout, model, do not change - no matter what the settings are or what ribbon tabs are checked or unchecked in the cui the ribbon ALWAYS shows the 3D Modeling tabs for user created workspaces. In addition all of the icons disappear from the quick access toolbar in user workspaces. I chalked this up to the ribbon customization issues you discussed in another thread but based on your comments above it sounds like something different. The inability to create enterprise or user workspaces that actually work is a serious hindrance and because of this I'm not rolling out '09.
Is this something I should be reporting to Autodesk or are they aware of this issue as well? Is it related to the ribbon customization issue? Am I (and the other two here) the only one having this issue?