Here's the list I've found so far:
On random occasions, moving from the a guest to the host causes SHIFT, CTRL, and ALT keys to stop working in the host. They continue to work fine in the guest. Only solution is to logout of X and login again.
Suspending a VM causes Workstation to hang after the suspend is complete. Only way to release it is to kill the vmware-vmx process. While it is hung, it is using CPU.
Logging off an X session (tested with Gnome) causes the guest machines to be effectively powered-off forthwith. No suspension, no backgrounding. This is despite the fact that "Run powered on VMs in background after close" is enabled in Workstation.
Using Workstation 6.5.2 build-156735