Create Virtual Machine with Preinstalled SharePoint 2010/2013 Development Environment.

Here are the steps you should follow in order to create a preinstalled environment on a virtual machine:

1. Install Windows Server 2008 R2/Windows Server 2012
2. Install SharePoint 2013/2010 with all updates and do not run SharePoint Configuration Wizard
3. You can install Visual Studio
4. You can install Microsoft Office
5. Do not install SQL Server because it can't be sysprepped.
6. Do not enter any domains. Just because it's useless and I haven't checked whether it works or not.
7. run C:\Windows\System32\Sysprep\Sysprep.exe
1. Make sure you've checked "Generalize" option:

8. Backup your virtual machine for later reuse

After you run your virtual environment you will need to:

1. Install Domain controller role if it's a standalone Development environment.
2. Join a domain (in case of SharePoint 2013) 
3. Install SQL Server (optional)
4. Run SharePoint Configuration Wizard

Conclusion:

There is only one mandatory step (Run SharePoint Configuration Wizard) you will need to do on your sysprepped virtual machine. Very convenient.