The music is so important to the GTA franchise. The right music while cruising in a particular vehicle in a particular location on the map is part of what makes the games great. I agree with basically bringing back the same stations as in GTA SA, with some updates. Several stations in particular I think are key:
You have to have a alternative/modern rock station like Radio X. Certain bands from GTA SA still fit well, like Rage Against the Machine, Soundgarden, Guns n' Roses, Stone Temple Pilots, and Alice in Chains, but I would also like to see Nirvana, Foo Fighters, Smashing Pumpkins, Red Hot Chili Peppers, The Killers, Bush, Incubus, Sublime, Rise Against, Weezer, 30 Seconds to Mars, etc.
You also need a classic rock station like K-DST for when you're cruising at high speeds through the country. The lineup from GTA SA is pretty solid.
A rap station like Radio Los Santos is essential for drivebys in the city. I actually like the idea of keeping the gangster rap era type of stuff like Dr. Dre, Ice Cube, Easy E, 2 Pac, NWA. You could certainly add Snoop Dogg. Maybe you could keep this station and also have a different one playing new rap.
I think a country station like K-Rose is good to have for committing drivebys on tractors and quads. The talk station is also entertaining and should stay. A pop station would also be reasonable.