Workstation 7 is FANTASTIC on Ubuntu 64. I'm so excited about this new workstation release as it provides many additional features over WS 6.5.

1) Sockets / Core selection - You can now set number of sockets and cores per socket to your individual workstation vm's.
2) Compacting of VM disk files can be done from workstation.
3) Encryption of Workstation VM's can now be done preventing access into VM's without proper credentials.
4) Windows 7 support

These are just a few of the options that are available, as well as, the ability to run nested ESX environments inside of Workstation 7.

If you are installing workstation for the first time on Ubuntu 64, you MUST execute the vmnetset script (http://communities.vmware.com/blogs/ecrossley/2009/06/29/ubuntu-and-vmware-workstation-networking) from this blog in order to allow promiscuous mode for your ethernet adapters