Do I really need to install 3.9 or any GUI?
Considering that AmigaOS/Workbench 3.x is TINY, there's very little reason not to install it.
It's not like it's going to fill your HD and it makes launching some apps easier, even if that's all you ever do with it..
Now, I haven't used 3.5/3.9, so I'm not sure there..
3.1 does everything I need and ClassicWB does it purty like. ;-)
desiv