I would like a way to compare two entries prior to a merge and have complete visiblity to what will happen. This would also be nice to have during the "Update from CDDB" and "Update from Amazon" operations.

My suggested ui for doing this would borrow from the diff tool "Beyond Compare" [url]http://www.scootersoftware.com/en/shot7w.png[/url]
Basicly there would be two columns (perhaps a third for the result?) that would contain all the info from the entries (including all track info so you don't miss any lyrics that might be in but not the other)

One use case for this would allow you to see the entry on the [url]www.freedb.org[/url] and compare to your local, without the risk of losing anything you have added locally.

Another use case is very similiar: merging the Amazon data with your own

Third use case: merging a cd entry with an MP3 entry