I had a requirement to compare User Profile data from SharePoint with AD data and I found this little tool to export all the AD users into CSV file. Nice and easy.
CSVDE -f c:\Temp\AD_Users.csv -r objectClass=user
Other example would be
CSVDE -f AD_Users.csv -r "(&(objectClass=user)(objectCategory=person)"
and
CSVDE -d "OU=Directors,DC=domain,dc=local" -f test.csv -r "(&(objectClass=user)(objectCategory=person)"
Ref: http://www.techrepublic.com/blog/data-center/simplify-admin-tasks-by-exporting-active-directory-data-with-csvde/#.