Could this be due to the way MC handles multiple artists albums, or albums that don't have the exact same artist tag for every track?
iTunes and some other taggers can get a little "creative" with the Artists tag. Sometimes adding unnecessary extra info to the Artist tag doing things like listing every performer for that track. That will cause MC to see the album as a multiple artists album and it will get treated and grouped differently in MC.
Here's two wiki articles on how MC deals with multiple artist albums:
Album Artist and Album Artist (Auto)Album Artist (auto)Those links will explain the background and basic rules of what you need to do in Media Center to get MC to see a multiple artists album as a single album. It makes sense once you know what is going on, but otherwise can be a bit confusing.
Make sure the Billy Joel best of album has all of its files in the same directory. Don't put tracks from multiple albums in the same directory (each album should have its own directory). See the wiki article for "Album Artist and Album Artist (Auto)" for the full list of rules. If those rules are followed MC will see the Billy Joel Best Of album as a single album.