If you need to keep the database online and you have another available LUN on your SAN, you could move all your clustered indexes, then your non-clustered indexes off to...
Also without knowing your entire situation and schema, I would take the NOT IN approach as it is slightly easier than the EXCEPT syntax. The EXCEPT syntax requires that...
I have been doing this operation with the LIKE operator in the past and have never thought of the PATINDEX operator. Both ways work well, i really can't find...
For performance purposes, have you considered dynamically specifying the FILLFACTOR on your index rebuilds to help with page splits and IO performance?