This is going to be a bit long, and not as easy as a simple tweak to the ini which we can no longer do but ....
A few more options - BACKUP your Skyrim - Sounds.bsa FIRST
The route I took was to use BSAOpt http://skyrim.nexusmods.com/downloads/file.php?id=247
Used it to extract the original sounds bsa (Choose the bsa as the source file - And for the destination choose a folder, and hit the Use Folder button) - This will extract the bsa to the folder and you will have a music and sounds folder within the destination.
Then copy the Music and Sounds folders to your In\ folder. Delete them from your Out\ folder.
Delete any music files you dont want - I just kept the special ones, and the Tavern music ( Kind of expect those to be in game, whereas anything that adds an invisible orchestra warning you of danger ... for me those had to go

)
Screenshot showing contents of my bsa http://www.bild.me/bild.php?file=2980913Untitled.png
To create the bsa, load up BSAOpt again, choose your In\ folder (the one with Music and Sounds folders inside, and 'Use Folder'
Important step: Go to the Game menu of BSAOpt, and choose Skyrim (BSAOpt defaults to creating bsa's for Oblivion if you leave it at automatic - So if you dont select Skyrim it will create a bsa in Oblivion format, and it will crash your game)
For Out\, click Browse, in the drop down menu near the bottom choose Save as type: Bethesda Softworks Archive, and give it a filename Skyrim - Sounds.bsa http://www.bild.me/bild.php?file=7439591Untitled2.png
Then you can either pack it up as a zip for your favourite mod manager to install (make sure you still have the original backed up somewhere just in case you are not happy with the results, or want to re-do with some music not deleted), or just drop it in data\ to overwrite the original.
Beware though in future, if you get steam to verify game files it will be replaced by a re-download of the genuine bsa, so needs re-installing.
I just pack them up as BAINs for Wrye Bash installation/Annealing.
It works fine for me so far - The game does not seem to care that it cannot find original game music files in the bsa
I though about replacing the original files with silent music files ... Emma (of Companion Vilja fame) has a tip for a tool which I think could be used for this ...
http://emmates.proboards.com/index.cgi?board=skyrim&action=display&thread=463
But so far have not had a need to try creating small silent sound files. It could for example be used to make silent sound files as replacers (the same way you use loose file texture replacers for the textures bsa - Body textures etc etc) .. So no need to mess with re-packing bsa's minus the music you dont want
Personally I just wanted to keep the clutter down in my data folder so went with re-doing the bsa instead.