I want to migrate from Ubuntu 12.04 Stand Alone to Ubuntu 12.04 as a virtual machine on a Windows 8 host - preferably with VirtualBox. What strategies can you propose to take over as much data and settings as possible?
Install VMware vCenter Converter Standalone in your Ubuntu. You can download from here if you create an account, its free:
Make sure you get the Linux version. The platform type can be found under details. The converter is able to create a virtual machine based on your physical machine, in this case your Ubuntu with all the programs you installed and all the data you wish to keep. Transfer the vm to an external disk or save it to an external disk during the conversion.
In your Windows 8 download VMware-player-5.0.1-894247.exe (its also free) from here:
Install VMware Player in Windows 8 and import your Ubuntu-Vm. After some fine-tuning and the installation of VMware Tools, which come with the player, you will have the same Ubuntu you had before, only now it is a virtual machine.
It is also possible to use the vm created by VMware vCenter on VirtualBox. For more information:
I would make a backup with clonezilla. After this I would start clonezilla in the VM and restore the backup. Don't forget: The transfer of data in a VM or on an other pc are the same.