Fitz,
As PGH said, Setanta is one reason, GolTV is a second and the package is the third. There are also some random spanish channels that show Euro games, World Cup qualifiers and Confed Cup. No idea if they are available on your local provider.
Setanta has many many more champions league games, WC qualifiers and presumably Euro qualifiers than any other channel. Not to mention it now also has EPL games. Between Setanta and FSC, you can pretty much watch every EPL game all season long.
GolTV shows Serie A and La Liga if those interest you. I don't follow Bundesliga, but I think they are also on GolTV. I don't believe that is availabel on local providers.
You get GolTV and FSC when you buy the FS package (~$12/month) and Setanta is as separate purchase for $12/mo. Directv also has an MLS, MLB, NBA, College Football, NFL and NHL package you can buy. And, I think it is actually cheaper than most regular providers (I know it is cheaper than Comcast).