V-Rock or Flash FM. Nothing to beat those two. Once in a while keep listening to VCPR though, since those talkshows are hilarious. But the addition of custom radiostations from San Andreas onward was very clever.
V-Rock on Vice City is by far the best. Even if I didnt enjoy Vice City as much as San Andreas, the music was deffinitly the best.
2nd choice would be Radio X on San Andreas, other wise all the stations on GTA 4 and GTA 3 were all shit.
I am not to sure what the stations were on Vice City stories as I only played about 15-20 hours so I can't really remember, however I am sure that they would be better than GTA 4 & 3
San Fierro Underground Radio with Hans =) and all the chatting programms
music wise -> Electro-Choc (it features Boys Noize, so bow to your master you maggots!) for the time being (08) it was pretty up-to-date with what you were hearing currently in the clubbing scene (good job for a game)
I've played 3, Vice City, Vice City Stories and San Andreas, and I think my favourite 2 stations are Emotion 98.3 and Wave, 103 but I like Flash FM a lot too. In San Andreas, I like about half the songs on both Radio: X and K-DST so I divide my time between those. V-Rock seems pretty good from what I've heard of it but I'm usually able to find something I like more on the other 3 channels which I usually listen to.