Was reading this over on Wired,
For many TV shows, costs to license the original music for DVD are prohibitively high, so rights owners replace the music with cheaper tunes, much to the irritation of avid fans. And some shows, like WKRP, which is full of music, will probably never make it to DVD because of high licensing costs.Now from what I can tell this only applies to the US
Only selected episodes from the first season of Ally McBeal have been released in the United States because of the high cost of music licensing. But in the United Kingdom, where different licensing deals have been struck, viewers can order all five seasons of the show.So If you are In the USA and are looking for a popular TV show on DVD that has been broadcast in the UK, you may want to try play.com and import them from the UK.
Don't know if you will be able to access the site from the US as it seems to know I am in the UK but don't see why not.