From Brent Ozar. Worth a read.

Stop Shrinking Your Database Files. Seriously. Now.

http://www.brentozar.com/archive/2009/08/stop-shrinking-your-database-files-seriously-now/

If you are going to shrink your database, at least put your NC indexes into a different filgroup and file and don't shrink that. Save yourself a lot of headaches.