How can I verify my wallet.dat file against an older version? I recently ran into an issue with an unsafe shutdown corruption on an NTFS partition in such a way that the files all existed, but chkdsk had to be run to verify some non-essential files.

My peers.dat file was the only file chkdsk complained about, but I verified my blockchain to be sure. How can I ensure my private keys in my current wallet.dat match the ones in my backup? I don't believe it is corrupt (At least Bitcoin-QT hasn't complained yet), but I'd rather be safe.
You can use the dumpwallet command and export the private keys to a text file. Do this for both wallets and then compare the text files. You should see the same addresses and private keys. If you do not, then something has gotten corrupted.