I'm running VMware Workstation on Windows 7 with an Ubuntu VM. After expanding the root filesystem, my shared folders stopped showing up under /mnt/hgfs.
Among the prompts you'll get when running the config script is a question specifically about enabling this feature.
The VMware Host-Guest Filesystem allows for shared folders between the host OS
and the guest OS in a Fusion or Workstation virtual environment. Do you wish
to enable this feature? [yes]