Our previous Exchange administrator would anually take the Exchange 2003 mailbox databases offline to run ESEUtil /d ISInteg -fix against the databases as a preventative maintenance measure. We have since moved to Exchange 2007, and the previous administrator has moved onto other things. Other then for defragging the mailbox store to recover disk space (which isn't really necessary for us anymore), is there any preventative maintance value to doing this regularly? I've not seen mention of this in the Exchange documentation I've gone through.

Nope. There isnt. An oldie but still true goodie:http://msexchangeteam.com/archive/2004/07/08/177574.aspxIs offline defragmentation considered regular Exchange maintenanceRegular running of Isinteg isnt required either - only when troubleshooting a specific issue or under direction of Microsoft support is it needed.