Well, I think I managed to get my iTunes library recreated after the PC move (which changed the path to the files, which frelled things up something awful), though with far more effort than it should have taken. Some resources that were of use (in close to this sequence, since the library file itself got frelled, though there were still backups):
http://support.apple.com/kb/HT1589
http://support.apple.com/kb/HT1451
http://ask.metafilter.com/70892/Fast-way-to-remove-thousands-of-duplicates-from-iTunes
And then it was a matter of finding a few hundred library entries that still didn't have associated files. It was a one-at-a-time effort, mostly, but Win7's Explorer makes searching for files a snap (relatively speaking).
Ugh. Apple, why do you make this so frelling difficult? (Answer: we want you to just us iTunes purchases and now our cloud offerings …) #ddtb
Embedded Link
How to open an alternate iTunes Library file or create a new one