By itself, I can imagine the music being not great...you know if your not a fan of pretty music interspersed with some of the best animated action ever made. However if you watch the whole episode it's better and if you watch the whole series (which by God you should) it's one of the...it's just fucking good.
This was about episode four, and we knew pretty much nothing about Spike before the out-the-window flashback montage. Another piece of info we pick up in this episode is that Spike keeps his grenades in the fridge.
Yes, the music and hamfisted religious imagery are awful, but I cannot in good conscience give Cowboy Bebop any less than four stars.
I kind of like the song. And the part where Jet fucks up his bonsai is brilliant. (Most of the best parts of that series are the interplay between Jet and Spike.)