Is there a way to save Avast configuration settings in a default config file that can be exported/imported to setup other machines?
There is not specifically an export/import settings function (something which has been asked for on numerous occasions), but you could try saving the various .ini files that are used when customisations are made.
XP location of the main avast5.ini file - C:\Documents and Settings\All Users\Application Data\Alwil Software\Avast5\avast5.ini. You should find other .ini files in there, these could be copied and pasted into the same location in the other system. However, you would need to disable the avast self-defence module to be able to replace the existing files (don’t forget to enable it after).
I don’t know how effective that might be, but personally I don’t see it as being that much of a benefit as for the most part people don’t stray much from the default settings.
Restore default settings function was supposedly planned for avast! 5.1 but i’m not sure if it will actually appear in this version.
We have four networked machines and I have several changes away from defaults, so it would be nice to have this function. Oh well, thanks for the info! 8)
Perhaps this feature will be in the new 5.1 version, but we are not certain. Hopefully it will be. 
Save the .ini files.
C:\ProgramData\Alwil Software\Avast5\avast5.ini and there are other .ini files for any of the Shields that you might have tweaked.
That is as best that you can do - You would have to disable the avast self-defence module to replace existing ini files when you reinstall/install. You would probably have to restart avast or the shields to get them to use the new ini files, probably easiest to reboot once you have done it.
Thank you, this is a very helpful forum community…kudos!