If you can't enable 3D-acceleration in your VMware VM (missing Aero, Unity not working, ...) then you should check your log-file in your VM directory. If it contains the message "GLManager: Required extension GL_EXT_texture_compression_s3tc is missing" you can try the following steps:
First thing to try is to install libtxc-dxtn for Mesa S3TC support on the Linux host. (On Ubuntu 'apt-get install libtxc-dxtn-s2tc0') After that please ensure that you've restarted VMware Player or Workstation.
Note: This is most of the time an issue with Intel-integrated graphics.
If this doesn't work you can force S3TC to be enabled. For this just install driconf on the Linux host (on Ubuntu 'apt-get install driconf'), run it and force S3TC on with the button on the Image Quality tab. After that please ensure that you've restarted VMware Player or Workstation.
Note #1: Forcing S3TC on might yield unexpected behavior!
Note #2: Forcing S3TC on is done by driconf by setting force_s3tc_enable=true in the ~/.drirc file. For a quick test this can be also done by just exporting force_s3tc_enable=true.
Link #1: http://askubuntu.com/questions/56379/is-there-an-easy-way-to-enable-s3tc-on-intel-graphics
Link #2: http://communities.vmware.com/thread/318693
