drwxrwxr-x 3 root admin 102 18 Dec 2009 /Library/Spotlight/Microsoft Entourage.mdimporter
drwxrwxr-x 3 root admin 102 21 Jan 2009 /Library/Spotlight/Microsoft Office.mdimporter
Didn't see anything out of the ordinary with your other output. I do observe there that two Microsoft importers exist... but i really have no idea if that's 'right' or 'wrong' (or acceptable or exceptional or what). Perhaps the Entourage import features are also covered by the Office importer. Perhaps that wouldn't matter anyway. (dunno)
Somehow, your problem probably runs deeper. Sorry to keep tossing terminal commands at you, but i'm hoping to see if anything unusual sticks out...
mdutil -s -a
^ to see what Spotlight considers the indexing status of all mounted volumes to be.
And...
ps axcu |sed '1p;/ md/!d'
^ to see which metadata processes are up and running.
