Everyone always talks about Daniel Ingram's musical contributions to the show, and while yes I can agree he does great work, I personally chalk up a lot of what makes this show so great musically and what makes each contribution on the show click together on William Anderson's works. This is similar to movies as well as TV; the musical cues serve as the underlying rhythm and tone of a scene that fills up the dead air between actor lines yet keep the audience engaged by the audio (versus the engagement visually by art and animation). The background music, as it seems to me, is the large fancy bow that ties the suit/room/decoration together. Usually background music is under appreciated in my opinion, so I really encourage everyone to check out whatever cartoon or tv show or movie you really like and see what the background music is doing, as I'm sure you will find that the music will be integral to what gives your favorite scenes the extra dramatic punch they deserve.
This is an easy task for anyone who has a smartphone/android/iphone/video ipod or what-have-you that can play videos on the move, but I'd encourage everyone to try this: listen to your favorite episodes as if it were a podcast i.e. only hearing the voices/sound effects and the music. You should be surprised at how many tight little musical cues are put into every line or action that might get swept up by looking at the visuals. Just imagining watching the show without the music should set off some alarms in your head that something crucial is missing.
Background music (in this context, for TV shows and music) can really enhance the show in this fashion: the music serves to enhance the tone of whatever scene it should be even further than what is possible by using visual tricks or voices which constitute our everyday lives (at the very least, MOST people don't have big fancy bands to play background music in their everyday lives). While we can see a visually epic scene accompanied by well-delivered dialogue and still get the message that "this is epic", the heroic horn line in the background slams this concept into the audience's mind further in ways the screen nor the voices can convey. Or consider a scary scene, there usually isn't much voice work going on, yet there will usually still be well-placed audio cues in the music via slow moving bass lines or a long tense string line to convey the same tenseness into the on-screen action for the viewers, usually followed by a sudden thunderous musical blast to change the mindset of the viewers and keep them on their seat. To me, I've always considered background music one of the most fundamental little workers in what makes this media work so effectively as an engaging art.
I've never studied this particular side of the music industry in depth before, so I'm sure Octavia can shed any light on that part, but I am constantly always amazed at what goes on in every single movie or TV show when everything works so well. William Anderson, you deserve a lot more praise than you've been getting, and you should be the one who gets skype calls at BroNYCon.
tl;dr version: Background music is amazing when done well and deserves more appreciation.
Edit: Hey look, a site that lists the shows bgms on youtube on other such bgm things!
It's a dream come true!