I use musicbrainz. It checks the correctness of tags against a database,
which I've had to add a good amount to (anyone can add info to the database, and
then its voted on). Once the tags are verified you can have the program sort
the files into folders set up to your liking and rename the files so
everything's uniform. I have mine sorted into
\artist name\album title [year]\track. title
\va\album title [year]\artist name - track - title
There's a separate setting for various artist albums.
It's a huge help, but you have to be careful about doing a huge batch at
once since it can make mistakes. I read on their site that their database
entries are going to be more thorough.
musicbrainz.org
ak