I've just installed Xubuntu 11.10 on my 64-bit machine, and downloaded and installed the 64-bit .deb package, and had the same awful font problem.

I followed the instructions on this page, which solved the problem: http://omgubuntu.co.uk/2012/01/how-to-make-google-earth-look-native-in-ubuntu

To paraphrase those instructions, do the following:

• In a terminal emulator, give the following commands:
• cd /opt/google/earth/
• sudo rm libcurl.so.4 libGLU.so.1 libnss_mdns4_minimal.so.2 libQtCore.so.4 libQtGui.so.4 libQtNetwork.so.4 libQtWebKit.so.4
• Use any editor to edit file /opt/google/earth/googleearth -- but you have to do it as a root, so for instance, the following command from a terminal emulator would work:
• sudo nano /opt/google/earth/googleearth
• Now add the line
  export LD_PRELOAD=libfreeimage.so.3
  as the second last line of file googleearth, and save the file.
• Download the file libfreeimage.so.3 from link http://ubuntuone.com/2f5PJTu25GqZG3Plmy5VjI, and save it in directory ~/Downloads /opt/google/earth/
• If your machine is 64-bit, download the file libphonon.so.4 from link http://ubuntuone.com/3MfWIy4xSNB7NOJLbBXNsA, and save it in directory /opt/google/earth/
• In a terminal emulator, give the following commands (the ones concerning libphonon.so.4 only if your machine is 64-bit):
• cd /opt/google/earth/
• sudo cp ~/Downloads/libfreeimage.so.3 .
• sudo cp ~/Downloads/libphonon.so.4 .
• sudo chmod a+x libfreeimage.so.3
• sudo chmod a+x libphonon.so.4
• sudo apt-get install libcurl4-openssl-dev libqtwebkit4

That worked for me.

Google really could do a better job of testing this Linux installation package before releasing it. I've grown used to quite high-quality software from Google, and this is unlike them.