Converting Tables to Ansi Padding On
This can be quite a tall order. My original thinking was that you could simply add a new version of each OFF column, copy the data over, drop the old column, and rename the new column. However there are a boatload of complications that will make this tedious or downright impossible:


constraints (including foreign keys) which will need to be disabled and/or dropped/re-created
computed columns
indexed views and other peripheral objects pointing at the affected table with SCHEMABINDING
the blocking this type of operation will cause on large tables
the mere complexity of generating an ALTER TABLE ADD script for each column, given that in 2008 R2 it is very cumbersome to derive the right data type from the metadata (it's easier in 2012, but still no picnic)




Honestly, I think the easiest thing to do would be to generate a script of the entire database:


right-click the database > tasks > generate scripts
if you get the intro screen, check the checkbox and click next
choose all objects and click next
on the "set scripting options" tab, click "Advanced"


Change "Types of data to script" to "schema and data"

on the same tab, change the output to "New query window"


In the resulting script, before running it, change all the references to the original database name to a new database name (including the file paths), and change all the ANSI_PADDING settings in the script to ON (using find/replace). Once the new database is created, you can rename the old database and rename the new one to the old name. Ultimately you can drop the old database once you've confirmed that everything is working correctly. 



Warning: do not try this in SQL Server 2014 CTP2 - In the process of answering this question, I lost some of my own work, due to this bug I just filed.