Since you can't shrink a LUN (Windows 2008 excepted) even if dedup has freed up space in the volume, we have to use thin provisioning in a SAN environment to realize deduplicated space savings.
Given the pain of getting caught having provisioned too much space (i.e. LUNs go offline), what are are you using for thin provisioning settings and monitoring? (Operations Manager, custom scripts, policies, etc.)