I had a MySQL 5.1 server completely crash due to hardware issues. We have a new server and I've installed a new instance of MySQL 5.1 and I have the MySQL dump which was created with the --all-databases switch. My question is can I simply just import that dump to the server including the 'mysql' and 'information_schema' databases w/o destroying the new installation?

i would exclude them, i think mysql created them automatically when you installed the new server

You can restore the dumps.
In Windows : Press windows+R => cmd

Use the following command to restore the dumps:

c:\>mysql -u < mysql user > -p< mysql password > -D <database name> < <filename of dump>

Ex: c:\>mysql -u root -p -D information_schema < mydump.dat

Check out My Blog