After running fsck with no change, a *nix geek friend of mine suggested I take a look at hidden files. I did so. No luck. Then I had the thought to check for hidden folders. Going through them, I noticed I had two entries in the .Trashes folder off the root drive, one for user 501, and the other for user 502.
Since my machine only had one account, and that is by default user 501, I got suspicious and took a look in 502. It was full of data. It had a complete applications folder in it, multiple copies of my current user account, etc. I had to use sudo to get into the directory to see the contents and delete them. Once I did so, my free space went from 1.5 gigs to 8 gigs.
I have no idea how that stuff showed up in there, but maybe this will help someone else who might have lost disk space they can't find.

