As some may remember, my favourite music service is Pandora (Deezer used to be a close second until they removed the "Hear This" feature). I listen to a lot of new music and discovery is important to me. That doesn't mean I want to explore a lot of genres I hate. There's a lot of good music in the world (in the sense of appealing to me) and I'd like to spend as much of my life as possible discovering those artists who will change my life for the better.
Pandora gets you there faster than anyone else. I'm currently listening to Carla Bruni radio. I only like Ms. Bruni's music about a 7 out of 10 but Pandora offers a mainly French female singer diet (way too much Ella Fitzgerald at first), leading me to discover four or five artists I didn't know. Pandora is also low-maintenance (it keeps playing without requiring adjusting playlists) and lets you tune your channels to your own tastes (no more Ella Fitzgerald much less Bossa Nova, lots more Indila, Andrea Lindsay, Thievery Corporation and Coeur de Pirate).