After upgrading to the x64 Infrastructure update, I opted to delete the
SearchCenter in one of my MOSS farms and re-add it with the new site
template.

Now, I'm noticing that the search results show the embedded title of the
documents, rather than the file name of the document.

It's doing this with everything... including documents indexed with the
Foxit PDF iFilter.

What appears to be going on is that the search engine is using the
document's Title Property, rather than the actual file name. Any
thoughts on how to fix this?