The TV spot (as well as the end credits for option B) has "Sleepwalking" by The Chain Gang of 1974, regarded by many fans as the best song in the game. Yes, it's that glorious.
"A.D.H.D." by Kendrick Lamar, a very catchy and atmospheric track that's perfect to play while driving around Los Santos at dusk.
The NWA's "Appetite For Destruction" is the first licensed song you hear in the game, playing as you joyride in the repossessed vehicles with Lamar. It serves as the perfect introduction to the city of Los Santos.
Really, Radio Mirror Park in general is an entire radio station full of awesome music (notably, some of the three ending songs and the opening theme for GTA Online all come from this station). A large number of series fans have declared it the best GTA Radio station ever.
Non-Stop Pop FM serves as a history lesson on pop music, from classic songs like Pet Shop Boys' "West End Girls" and Wham's "Everything She Wants", to 90's dance hits like Corona's "Rhythm of the Night" and Stardust's "Music Sounds Better With You", ending with present day songs like Rihanna's "Only Girl in the World". All this comes together to provide the perfect backdrop for the glamour and heartbreaks of Los Santos.
FlyLo FM is a mix of experimental and eclectic music, including Hudson Mohawke's monstrous "100HM", Thundercat's smooth "Oh Sheit It's X" and Tyler, The Creator's haunting "Garbage". It also includes a few classic tracks such as Outkast's "Elevators (Me & You)" and Aphex Twin's "Windowlicker" for good measure.