58 of them are actually used in-game, while 35 are left unused.

(If you're wondering, the backgrounds and cutscenes folders are empty.)
Here's the list of the unused songs:
Code: Select all
music\ogg\songs\baltimore\clutch_a_shogun_named_marcus.ogg
music\ogg\songs\dc\q_and_not_u_lax.ogg
music\ogg\songs\NATIONAL\alien_sex_fiend_i_walk_the_line.ogg
music\ogg\songs\NATIONAL\beck_cellphones_dead.ogg
music\ogg\songs\NATIONAL\celtic_frost_into_the_crypts_of_rays.ogg
music\ogg\songs\NATIONAL\dj_krush_kill_switch.ogg
music\ogg\songs\NATIONAL\eels_souljacker_part_1.ogg
music\ogg\songs\NATIONAL\erik_b_and_rakim_follow_the_leader.ogg
music\ogg\songs\NATIONAL\evilnine_crooked.ogg
music\ogg\songs\NATIONAL\faruk_green_faith.ogg
music\ogg\songs\NATIONAL\haunted_dark_intentions.ogg
music\ogg\songs\NATIONAL\james_pants_do_a_couple_of_things.ogg
music\ogg\songs\NATIONAL\jawbox_secrethistory.ogg
music\ogg\songs\NATIONAL\jesus_lizard_cold_water.ogg
music\ogg\songs\NATIONAL\julietteandthelicks_gotlovetokill.ogg
music\ogg\songs\NATIONAL\masta_ace_incorporated_born_to_roll.ogg
music\ogg\songs\NATIONAL\minor_threat_filler.ogg
music\ogg\songs\NATIONAL\moving_units_going_for_adds.ogg
music\ogg\songs\NATIONAL\nailbomb_wasting_away.ogg
music\ogg\songs\NATIONAL\ponce_deleon_gator_jaws.ogg
music\ogg\songs\NATIONAL\sex_pistols_pretty_vacant.ogg
music\ogg\songs\NATIONAL\slayer_angel_of_death.ogg
music\ogg\songs\NATIONAL\speedealer_screamer.ogg
music\ogg\songs\NATIONAL\stephenmarley_mindcontrol.ogg
music\ogg\songs\NATIONAL\the_accused_psychomania.ogg
music\ogg\songs\NATIONAL\the_exploited_law_and_order.ogg
music\ogg\songs\NATIONAL\the_horrors_sheena_is_a_parasite.ogg
music\ogg\songs\NATIONAL\the_pack_vans.ogg
music\ogg\songs\NATIONAL\the_roots_here_i_come.ogg
music\ogg\songs\NATIONAL\thecribs_heyscenesters.ogg
music\ogg\songs\NATIONAL\threeinchesofblood_nightmarauders.ogg
music\ogg\songs\NATIONAL\treacherous_three_body_rock.ogg
music\ogg\songs\NATIONAL\tv_on_the_radio_playmates.ogg
music\ogg\songs\NATIONAL\unkle_the_knock.ogg
music\ogg\songs\NATIONAL\wire_12xu.ogg
If you notice, there are two other folders in the songs folder: baltimore and dc
And they both contain a song that isn't used.
"Angel of Death" is probably a THP8 leftover, since it sounds almost identical to the THP8 version.
All these songs (apart from Angel of Death) are also left unedited, meaning that the profanity wasn't censored.
Here's the music decoded into normal OGG: Download
Thanks to hcs64 for the vid1_2ogg tool.